Fix potential XSS vulnerability in rename hint

The file name displayed in the rename hint should be escaped to avoid
XSS. Note that this vulnerability is only applicable when an attacker
has gained push access to the repository.

Signed-off-by: Lukas Fleischer <cgit@cryptocrack.de>
Signed-off-by: Lars Hjemli <hjemli@gmail.com>

ui-diff.c

@@ -97,10 +97,12 @@ static void print_fileinfo(struct fileinfo *info)
 	htmlf("</td><td class='%s'>", class);
 	cgit_diff_link(info->new_path, NULL, NULL, ctx.qry.head, ctx.qry.sha1,
 		       ctx.qry.sha2, info->new_path, 0);
-	if (info->status == DIFF_STATUS_COPIED || info->status == DIFF_STATUS_RENAMED)
-		htmlf(" (%s from %s)",
-		      info->status == DIFF_STATUS_COPIED ? "copied" : "renamed",
-		      info->old_path);
+	if (info->status == DIFF_STATUS_COPIED || info->status == DIFF_STATUS_RENAMED) {
+		htmlf(" (%s from ",
+		      info->status == DIFF_STATUS_COPIED ? "copied" : "renamed");
+		html_txt(info->old_path);
+		html(")");
+	}
 	html("</td><td class='right'>");
 	if (info->binary) {
 		htmlf("bin</td><td class='graph'>%ld -> %ld bytes",