-Optionally, you can pass a regular expression that tells Git what the
-words are that you are looking for; The default is to interpret any
-stretch of non-whitespace as a word.
+When a <regex> is specified, every non-overlapping match of the
+<regex> is considered a word. Anything between these matches is
+considered whitespace and ignored(!) for the purposes of finding
+differences. You may want to append `|[^[:space:]]` to your regular
+expression to make sure that it matches all non-whitespace characters.
+A match that contains a newline is silently truncated(!) at the
+newline.