all: single space after period.

The tree's pretty inconsistent about single space vs double space
after a period in documentation. Make it consistently a single space,
per earlier decisions. This means contributors won't be confused by
misleading precedence.

This CL doesn't use go/doc to parse. It only addresses // comments.
It was generated with:

$ perl -i -npe 's,^(\s*// .+[a-z]\.)  +([A-Z]),$1 $2,' $(git grep -l -E '^\s*//(.+\.)  +([A-Z])')
$ go test go/doc -update

Change-Id: Iccdb99c37c797ef1f804a94b22ba5ee4b500c4f7
Reviewed-on: https://go-review.googlesource.com/20022
Reviewed-by: Rob Pike <[email protected]>
Reviewed-by: Dave Day <[email protected]>
Run-TryBot: Brad Fitzpatrick <[email protected]>
TryBot-Result: Gobot Gobot <[email protected]>

src/archive/tar/writer.go

@@ -316,8 +316,8 @@ func (tw *Writer) writePAXHeader(hdr *Header, paxHeaders map[string]string) erro
 	// succeed, and seems harmless enough.
 	ext.ModTime = hdr.ModTime
 	// The spec asks that we namespace our pseudo files
-	// with the current pid.  However, this results in differing outputs
-	// for identical inputs.  As such, the constant 0 is now used instead.
+	// with the current pid. However, this results in differing outputs
+	// for identical inputs. As such, the constant 0 is now used instead.
 	// golang.org/issue/12358
 	dir, file := path.Split(hdr.Name)
 	fullName := path.Join(dir, "PaxHeaders.0", file)

src/bufio/bufio.go

@@ -234,7 +234,7 @@ func (b *Reader) ReadByte() (byte, error) {
 	return c, nil
 }
 
-// UnreadByte unreads the last byte.  Only the most recently read byte can be unread.
+// UnreadByte unreads the last byte. Only the most recently read byte can be unread.
 func (b *Reader) UnreadByte() error {
 	if b.lastByte < 0 || b.r == 0 && b.w > 0 {
 		return ErrInvalidUnreadByte
@@ -273,7 +273,7 @@ func (b *Reader) ReadRune() (r rune, size int, err error) {
 	return r, size, nil
 }
 
-// UnreadRune unreads the last rune.  If the most recent read operation on
+// UnreadRune unreads the last rune. If the most recent read operation on
 // the buffer was not a ReadRune, UnreadRune returns an error.  (In this
 // regard it is stricter than UnreadByte, which will unread the last byte
 // from any read operation.)

src/bytes/buffer.go

@@ -44,7 +44,7 @@ var ErrTooLarge = errors.New("bytes.Buffer: too large")
 func (b *Buffer) Bytes() []byte { return b.buf[b.off:] }
 
 // String returns the contents of the unread portion of the buffer
-// as a string.  If the Buffer is a nil pointer, it returns "<nil>".
+// as a string. If the Buffer is a nil pointer, it returns "<nil>".
 func (b *Buffer) String() string {
 	if b == nil {
 		// Special case, useful in debugging.
@@ -145,7 +145,7 @@ func (b *Buffer) WriteString(s string) (n int, err error) {
 }
 
 // MinRead is the minimum slice size passed to a Read call by
-// Buffer.ReadFrom.  As long as the Buffer has at least MinRead bytes beyond
+// Buffer.ReadFrom. As long as the Buffer has at least MinRead bytes beyond
 // what is required to hold the contents of r, ReadFrom will not grow the
 // underlying buffer.
 const MinRead = 512
@@ -252,7 +252,7 @@ func (b *Buffer) WriteRune(r rune) (n int, err error) {
 }
 
 // Read reads the next len(p) bytes from the buffer or until the buffer
-// is drained.  The return value n is the number of bytes read.  If the
+// is drained. The return value n is the number of bytes read. If the
 // buffer has no data to return, err is io.EOF (unless len(p) is zero);
 // otherwise it is nil.
 func (b *Buffer) Read(p []byte) (n int, err error) {
@@ -347,7 +347,7 @@ func (b *Buffer) UnreadRune() error {
 }
 
 // UnreadByte unreads the last byte returned by the most recent
-// read operation.  If write has happened since the last read, UnreadByte
+// read operation. If write has happened since the last read, UnreadByte
 // returns an error.
 func (b *Buffer) UnreadByte() error {
 	if b.lastRead != opReadRune && b.lastRead != opRead {
@@ -400,7 +400,7 @@ func (b *Buffer) ReadString(delim byte) (line string, err error) {
 }
 
 // NewBuffer creates and initializes a new Buffer using buf as its initial
-// contents.  It is intended to prepare a Buffer to read existing data.  It
+// contents. It is intended to prepare a Buffer to read existing data. It
 // can also be used to size the internal buffer for writing. To do that,
 // buf should have the desired capacity but a length of zero.
 //

src/bytes/bytes.go

@@ -164,7 +164,7 @@ func IndexRune(s []byte, r rune) int {
 
 // IndexAny interprets s as a sequence of UTF-8-encoded Unicode code points.
 // It returns the byte index of the first occurrence in s of any of the Unicode
-// code points in chars.  It returns -1 if chars is empty or if there is no code
+// code points in chars. It returns -1 if chars is empty or if there is no code
 // point in common.
 func IndexAny(s []byte, chars string) int {
 	if len(chars) > 0 {
@@ -188,8 +188,8 @@ func IndexAny(s []byte, chars string) int {
 }
 
 // LastIndexAny interprets s as a sequence of UTF-8-encoded Unicode code
-// points.  It returns the byte index of the last occurrence in s of any of
-// the Unicode code points in chars.  It returns -1 if chars is empty or if
+// points. It returns the byte index of the last occurrence in s of any of
+// the Unicode code points in chars. It returns -1 if chars is empty or if
 // there is no code point in common.
 func LastIndexAny(s []byte, chars string) int {
 	if len(chars) > 0 {
@@ -276,7 +276,7 @@ func Fields(s []byte) [][]byte {
 
 // FieldsFunc interprets s as a sequence of UTF-8-encoded Unicode code points.
 // It splits the slice s at each run of code points c satisfying f(c) and
-// returns a slice of subslices of s.  If all code points in s satisfy f(c), or
+// returns a slice of subslices of s. If all code points in s satisfy f(c), or
 // len(s) == 0, an empty slice is returned.
 // FieldsFunc makes no guarantees about the order in which it calls f(c).
 // If f does not return consistent results for a given c, FieldsFunc may crash.
@@ -352,12 +352,12 @@ func HasSuffix(s, suffix []byte) bool {
 
 // Map returns a copy of the byte slice s with all its characters modified
 // according to the mapping function. If mapping returns a negative value, the character is
-// dropped from the string with no replacement.  The characters in s and the
+// dropped from the string with no replacement. The characters in s and the
 // output are interpreted as UTF-8-encoded Unicode code points.
 func Map(mapping func(r rune) rune, s []byte) []byte {
 	// In the worst case, the slice can grow when mapped, making
-	// things unpleasant.  But it's so rare we barge in assuming it's
-	// fine.  It could also shrink but that falls out naturally.
+	// things unpleasant. But it's so rare we barge in assuming it's
+	// fine. It could also shrink but that falls out naturally.
 	maxbytes := len(s) // length of b
 	nbytes := 0        // number of bytes encoded in b
 	b := make([]byte, maxbytes)
@@ -697,7 +697,7 @@ func EqualFold(s, t []byte) bool {
 			return false
 		}
 
-		// General case.  SimpleFold(x) returns the next equivalent rune > x
+		// General case. SimpleFold(x) returns the next equivalent rune > x
 		// or wraps around to smaller values.
 		r := unicode.SimpleFold(sr)
 		for r != sr && r < tr {
@@ -709,6 +709,6 @@ func EqualFold(s, t []byte) bool {
 		return false
 	}
 
-	// One string is empty.  Are both?
+	// One string is empty. Are both?
 	return len(s) == len(t)
 }

src/bytes/bytes_test.go

@@ -113,7 +113,7 @@ func TestEqualExhaustive(t *testing.T) {
 	}
 }
 
-// make sure Equal returns false for minimally different strings.  The data
+// make sure Equal returns false for minimally different strings. The data
 // is all zeros except for a single one in one location.
 func TestNotEqual(t *testing.T) {
 	var size = 128
@@ -797,7 +797,7 @@ func TestMap(t *testing.T) {
 	// Run a couple of awful growth/shrinkage tests
 	a := tenRunes('a')
 
-	// 1.  Grow.  This triggers two reallocations in Map.
+	// 1.  Grow. This triggers two reallocations in Map.
 	maxRune := func(r rune) rune { return unicode.MaxRune }
 	m := Map(maxRune, []byte(a))
 	expect := tenRunes(unicode.MaxRune)

src/bytes/compare_test.go

@@ -62,7 +62,7 @@ func TestCompareBytes(t *testing.T) {
 	a := make([]byte, n+1)
 	b := make([]byte, n+1)
 	for len := 0; len < 128; len++ {
-		// randomish but deterministic data.  No 0 or 255.
+		// randomish but deterministic data. No 0 or 255.
 		for i := 0; i < len; i++ {
 			a[i] = byte(1 + 31*i%254)
 			b[i] = byte(1 + 31*i%254)

src/bytes/equal_test.go

@@ -14,11 +14,11 @@ import (
 )
 
 // This file tests the situation where memeq is checking
-// data very near to a page boundary.  We want to make sure
+// data very near to a page boundary. We want to make sure
 // equal does not read across the boundary and cause a page
 // fault where it shouldn't.
 
-// This test runs only on linux.  The code being tested is
+// This test runs only on linux. The code being tested is
 // not OS-specific, so it does not need to be tested on all
 // operating systems.
 

src/cmd/cgo/ast.go

@@ -40,7 +40,7 @@ func sourceLine(n ast.Node) int {
 }
 
 // ReadGo populates f with information learned from reading the
-// Go source file with the given file name.  It gathers the C preamble
+// Go source file with the given file name. It gathers the C preamble
 // attached to the import "C" comment, a list of references to C.xxx,
 // a list of exported functions, and the actual AST, to be rewritten and
 // printed.