Fix restart check running after semicolon append

Co-authored-by: swissspidy <841956+swissspidy@users.noreply.github.com>

Author: Copilot

src/WP_CLI/Shell/REPL.php

@@ -49,14 +49,15 @@ public function start() {
 			if ( 'exit' === trim( $__repl_input_line ) ) {
 				return 0;
 			}
-			$__repl_input_line = rtrim( $__repl_input_line, ';' ) . ';';
 
 			// Check for special restart command
 			if ( 'restart' === trim( $__repl_input_line ) ) {
 				WP_CLI::log( 'Restarting shell...' );
 				return self::EXIT_CODE_RESTART;
 			}
 
+			$__repl_input_line = rtrim( $__repl_input_line, ';' ) . ';';
+
 			if ( self::starts_with( self::non_expressions(), $__repl_input_line ) ) {
 				ob_start();
 				// phpcs:ignore Squiz.PHP.Eval.Discouraged -- This is meant to be a REPL, no way to avoid eval.