ui-refs: escape HTML chars in author and tagger names

Everywhere else we use html_txt to escape any special characters in
these variables.  Do so here as well.

Signed-off-by: John Keeping <john@keeping.me.uk>

ui-refs.c

@@ -155,9 +155,9 @@ static int print_tag(struct refinfo *ref)
 	html("</td><td>");
 	if (info) {
 		if (info->tagger)
-			html(info->tagger);
+			html_txt(info->tagger);
 	} else if (ref->object->type == OBJ_COMMIT) {
-		html(ref->commit->author);
+		html_txt(ref->commit->author);
 	}
 	html("</td><td colspan='2'>");
 	if (info) {