userdiff: support enum keyword in PHP hunk header

"enum" keyword will be introduced in PHP 8.1.
https://wiki.php.net/rfc/enumerations

Signed-off-by: USAMI Kenta <tadsan@zonu.me>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/t/t4018/php-enum b/t/t4018/php-enum
new file mode 100644
index 0000000000..91a69c1a2b
--- /dev/null
+++ b/t/t4018/php-enum
@@ -0,0 +1,4 @@
+enum RIGHT: string
+{
+    case Foo = 'ChangeMe';
+}