`cancel_macro` command

[folospior]

The default binding to record a macro is Q. To replay it, it's q. It's really easy to mess them up. Personally, it happens to me whenever I use macros 😂

Nevertheless, it would be quite useful to anyone to cancel recording a macro and not overwrite the buffer.
I'd suggest either <C>q or <space>q as the binds to cancel recording, but even :cancel_macro would be quite useful.