Add entering normal mode as autosave trigger

[TobTobXX]

For me, autosave is an essential feature. But the 'unfocus' trigger doesn't work, since autosave also triggrers reformatting (which I think is useful), but causes a massive loss of context when triggered on unfocus. (I'd switch workspaces to copy some code and bam! autoformat moved my cursor around when I look back...)

However, when exiting edit mode, it's quite natural, as I've finished doing my edit, I actually want the formatter to clean it up. It is also a rather logical time to autosave, since I've just made an edit.

TODOs

• Documentation: Wasn't there a command to generate the book documentations? Nope, that's just for :commands I think.
• Don't break compatibility: Autosave all when the terminal loses focus #3178 (comment)
• Update modification indicator in statusline after autosave.

See also:

• Discussion: Auto-save #3451
• Conflicts with Add save on idle 🚀 #5303 (Rebasing is easy, just inform me whether this or the other PR should be the lower commit)

[TobTobXX]

Note, that the last TODO (updating statusline) doesn't work with the unfocus trigger either. *shrug

[TobTobXX]

Ugh, thanks to this stupid comment the config is now quite a bit uglier and more indirect.

btw, can we ignore clippy on helix-view/src/editor.rs:1699:9? That hint, while technically correct, is really NOT helping readability.

[archseer]

Do we really need another config option? We could just trigger on both

\cc @groves

[pascalkuthe]

I am not sure this even needs to be build in. I have just bound esc to [normal_mode, :w<ret>] works well enough for saving on exting insert modem It doesn't quite catch all instances of exiting normal mode but it's good enough for the most part.

I think in the long run we would want something more flexible to save (after a decently long denounced timeout) after every edit so doing edits in normal.mode (replace, paste, rename) also triggers autosave. Until such a solution is.implemented I think the keybindkng above is a good enough workaround

[TobTobXX]

Ok, I'll yield. Your point is valid.