completion: complete "diff --word-diff-regex="

Signed-off-by: Thomas Braun <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: t-b

contrib/completion/git-completion.bash

@@ -1168,7 +1168,7 @@ __git_diff_common_options="--stat --numstat --shortstat --summary
 			--no-prefix --src-prefix= --dst-prefix=
 			--inter-hunk-context=
 			--patience --histogram --minimal
-			--raw --word-diff
+			--raw --word-diff --word-diff-regex=
 			--dirstat --dirstat= --dirstat-by-file
 			--dirstat-by-file= --cumulative
 			--diff-algorithm=