Shell: Highlight redirections

Author: https://github.com/alimpfard
Commit: 2714bba3f0
Pull-request: https://github.com/SerenityOS/serenity/pull/2528
Reviewed-by: https://github.com/awesomekling

Shell/Parser.h

@@ -61,6 +61,7 @@ struct Redirection {
     Type type;
     int fd { -1 };
     int rewire_fd { -1 };
+    size_t redirection_op_start { 0 };
     Token path {};
 };