I'm trying to open a file with a given encoding and running into the problem that C-m is the same as RET. There is an answer here. However, I don't want to bind a specific function; I want to restore all C-x C-m key bindings to their intended behavior; so, the next time I look up how to do something, it just works.

This raises the question of why there even are C-x C-m bindings if they don't work. Note I'm assuming this documentation is correct. I don't know how to look up the command for the binding. If I use C-h k to describe the command, I'm still stuck with the problem of how to type C-x C-m!

I also looked at this answer, but I'm not clear if he's saying it can't be done, or is it only in a terminal that it's a problem? I'm only using emacs in a GUI; I can't remember the last time I used it in a terminal. I'm open to workarounds, such as using a different key. The trouble with this is I won't remember it has been remapped unless I use it frequently...