Refactor wrap_code to apply filters before concatenation

Author: louiswol94

src/php/flat-files/handlers/php-snippet-handler.php

@@ -12,7 +12,7 @@ public function get_dir_name(): string {
 	}
 
 	public function wrap_code( string $code ): string {
-		$code = "<?php\n\n" . $code;
-		return apply_filters( 'code_snippets_php_snippet_file_code', $code );
+		$output = "<?php\n\n" . apply_filters( 'code_snippets_php_snippet_file_code', $code );
+		return $output;
 	}
 }