finfo, despite being lowercase, is a class

grepping for "all the return typehints in `generated/`", it appears that this and `stdClass` are the only lowercase classes:

```
sl grep '^function' | cut -d: -f3 | sort | uniq
```

Author: shish

generated/8.1/fileinfo.php

@@ -14,9 +14,12 @@ private static function isClass(string $type): bool
         if ($type === '') {
             return false;
         }
-        if ($type === 'stdClass') {
+
+        // Non-standard lowercase classes
+        if (in_array($type, ['stdClass', 'finfo'])) {
             return true;
         }
+
         // Classes start with uppercase letters. Otherwise, it's most likely a scalar.
         if ($type[0] === strtoupper($type[0])) {
             return true;