Revert jarun#1398: Go to prev dir on bookmark key repeat

Reasons:

1. `b` is not a special key and will be interpreted as a filter
2. with this change pressing the standard `-` inside a symlinked
   bookmark takes back to the bookmarks directory. This deviates
   from the regular bookmarks behaviour.

nnn.1

@@ -363,9 +363,6 @@ There are 2 ways (can be used together) to manage bookmarks.
 On entering a bookmark, the directory where the select bookmark key was
 pressed is set as the previous directory. Press '-' to return to it.
 .Pp
-When \fINNN_BMS\fR` is not set, it's possible to return to the previous directory
-from the bookmarks directory using the select bookmark key.
-.Pp
 .Sh UNITS
 The minimum file size unit is byte (B). The rest are K, M, G, T, P, E, Z, Y
 (powers of 1024), same as the default units in \fIls\fR.

src/nnn.c

@@ -7144,13 +7144,8 @@ static bool browse(char *ipath, const char *session, int pkey)
 					goto nochange;
 				}
 
-				if (strcmp(path, newpath) == 0) {
-					if (bookmark || !*lastdir)
-						break;
-
-					dir = lastdir; /* Go to last dir on bookmark key repeat */
-					xstrsncpy(newpath, dir, PATH_MAX);
-				}
+				if (strcmp(path, newpath) == 0)
+					break;
 			}
 
 			/* In list mode, retain the last file name to highlight it, if possible */