Wiki/Documentation: Suggested function name should be diff_wordsToChars

[ztiromoritz]

In the first sentence in the section about a word mode:

https://github.com/google/diff-match-patch/wiki/Line-or-Word-Diffs#word-mode

Computing a word-mode diff is exactly the same as the line-mode diff, except you will have to make a copy of diff_linesToChars and call it diff_linesToWords.

The function should be renamed to "diff_wordsToChars", not "diff_linesToWords".

Because words will be mapped to single chars, if you do the suggested modification. Analogous to lines that will be mapped to single chars in the original function.