Add default keybindings for rename-ns-alias and add-arity refactorings, and refactor clojure-unwind

[yuhan0]

I placed these suggested bindings under the clojure-refactor-map and added them to the menubar:
C-c C-r n r -> clojure-rename-ns-alias
C-c C-r a -> clojure-add-arity

The a keybinding was taken by clojure-unwind-all which didn't made much sense, so I took the liberty of changing it to U as a "stronger" version of the existing u -> clojure-unwind binding.

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[bbatsov]

The a keybinding was taken by clojure-unwind-all which didn't made much sense, so I took the liberty of changing it to U as a "stronger" version of the existing u -> clojure-unwind binding.

Uppercase bindings are both hard to press and a bit confusing for the end users, so I generally avoid them. Probably in this case we can fold a few of the *-all commands into the parent commands and make the invokable with a prefix arg.

[yuhan0]

Would you like that to be done in this PR? It sounds like quite a big breaking change and personally I prefer having separate commands for discoverability instead of using prefix args.

Another option in this case could be u w -> unwind and u a -> unwind-all, or u for one and C-u for the other, although that would somewhat break symmetry with the rest of the bindings.

[bbatsov]

Would you like that to be done in this PR? It sounds like quite a big breaking change and personally I prefer having separate commands for discoverability instead of using prefix args.

That makes sense under a certain point - when you start running out of meaningful keybindings you know you have to start compacting things and group them together. I'm not saying to remove the existing command - I'm just saying to remove its dedicated keybinding. I think such commands are a classic use case for a prefix key as technically this is just an extension of the core behaviour.

Changing the existing key is just as big of a breaking change as far as I'm concerned, so nothing really changes in the end.

Another option in this case could be u w -> unwind and u a -> unwind-all, or u for one and C-u for the other, although that would somewhat break symmetry with the rest of the bindings.

Extra prefixes should be utilized only to group multiple related commands. E.g. - if we had more commands that operated on function definitions it would make sense to put them under some shared prefix.

[yuhan0]

Ok, I refactored clojure-unwind to take a numeric prefix / universal argument, and removed the dedicated key binding for clojure-unwind-all

[bbatsov]

The changes look great! Don't forget to update the changelog as well.

[yuhan0]

Done, and added a couple of tests as well :)

[bbatsov]

Lovely! Thank you! 🙇