Refactoring: Use ingo#regexp#split#TopLevelBranches()

This function provides an extended version of the split() that was previously used here.

autoload/mark.vim

@@ -1,19 +1,23 @@
 " Script Name: mark.vim
 " Description: Highlight several words in different colors simultaneously.
 "
-" Copyright:   (C) 2008-2015 Ingo Karkat
+" Copyright:   (C) 2008-2018 Ingo Karkat
 "              (C) 2005-2008 Yuheng Xie
 "   The VIM LICENSE applies to this script; see ':help copyright'.
 "
 " Maintainer:  Ingo Karkat <[email protected]>
 "
-" Dependencies:
+" DEPENDENCIES:
+"   - ingo/cmdargs/pattern.vim autoload script
+"   - ingo/err.vim autoload script
+"   - ingo/msg.vim autoload script
+"   - ingo/regexp/split.vim autoload script
 "	- ingo/cmdargs/pattern.vim autoload script
 "	- ingo/err.vim autoload script
 "	- ingo/msg.vim autoload script
 "	- SearchSpecial.vim autoload script (optional, for improved search messages).
 "
-" Version:     3.0.0
+" Version:     3.0.1
 " Changes:
 " 26-May-2015 Ingo Karkat
 " - CHG: Parse :Mark arguments as either /{pattern}/ or whole {word}.
@@ -617,7 +621,7 @@ function! s:EchoMarksDisabled()
 endfunction
 
 function! s:SplitIntoAlternatives( pattern )
-	return split(a:pattern, '\%(\%(^\|[^\\]\)\%(\\\\\)*\\\)\@<!\\|')
+	return ingo#regexp#split#TopLevelBranches(a:pattern)
 endfunction
 
 " Return [success, markGroupNum]. success is true when the mark has been set or

doc/mark.txt

@@ -317,7 +317,7 @@ To uninstall, use the |:RmVimball| command.
 DEPENDENCIES						   *mark-dependencies*
 
 - Requires Vim 7.1 with |matchadd()|, or Vim 7.2 or higher.
-- Requires the |ingo-library.vim| plugin (vimscript #4433), version 1.020 or
+- Requires the |ingo-library.vim| plugin (vimscript #4433), version 1.034 or
   higher.
 
 ==============================================================================
@@ -503,6 +503,9 @@ https://github.com/inkarkat/vim-mark/issues or email (address below).
 ==============================================================================
 HISTORY								*mark-history*
 
+3.0.1	RELEASEME
+  *** You need to update to ingo-library (vimscript #4433) version 1.034! ***
+
 3.0.0	18-Sep-2017
 - CHG: Parse :Mark arguments as either /{pattern}/ or whole {word}. This
   better addresses the common use case of searching for whole words, and is