diff: add ruby funcname pattern

Provide a regexp that catches class, module and method definitions in
Ruby scripts, since the built-in default only finds classes.

Signed-off-by: Giuseppe Bilotta <giuseppe.bilotta@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff.c

@@ -1381,6 +1381,7 @@ static struct builtin_funcname_pattern {
 			"[A-Za-z_][A-Za-z_0-9]*\\)\\{2,\\}"
 			"[ 	]*([^;]*\\)$" },
 	{ "tex", "^\\(\\\\\\(sub\\)*section{.*\\)$" },
+	{ "ruby", "^\\s*\\(\\(class\\|module\\|def\\)\\s.*\\)$" },
 };
 
 static const char *diff_funcname_pattern(struct diff_filespec *one)