Add editor setting to toggle automatic code completion

[quinnyo]

This adds a boolean editor setting (text_editor/completion/auto_code_complete) and implementation in the code editor to allow automatic code completion to be disabled. It's a pretty small, straightforward change, I think -- but I don't know what I did wrong yet!

Fixes #68139.

[MewPurPur]

I'm on board with the idea. Code LGTM, can't think of anything that could possibly go wrong (famous last words)

[Mickeon]

I mean, sure! The editor setting makes sense on its own, but... quoting the issue:

I find the built-in code completion to be quite aggressive/invasive. It often makes editing scripts stressful, unpleasant and time-consuming.

the fact that the autocompletion in 4.0 is SO ATROCIOUSLY invasive users may want to outright disable it unless manually brought up is quite damning evidence that perhaps something more should be... done about it.

• Feels like I urgently need to get back adjusting Sort code autocompletion options by similarity based on input #65655. It's part of the things that would at least make it more usable.

[Paulb23]

Rather then adding a new setting, would it be worth making a delay of 0 disable it?

[Riteo]

@Paulb23 that doesn't sound very intuitive to me. Is it possible to set it to a negative value? That'd map much better, but it may still be less user-friendly than a plain toggle.

[quinnyo]

synced with master

[quinnyo]

Some notes based on comments here and in the issue:

Improving the suggestions themselves is a worthy endeavour, but it is a separate one. The fact that the suggestions pop up automatically is the issue. It doesn't matter how good the suggestions are.

I don't think overloading the delay setting (i.e. allowing an out of range or practically infinite value) is a good way to go. It's messy and less obvious than a dedicated setting.
Having a dedicated setting communicates very clearly that you can turn the feature on/off. It also allows keeping your preferred value, if/when the feature is re-enabled.

[akien-mga]

I support adding this.

I'm not sure about the name of the setting though. auto_code_complete sounds like the code would be completed automatically, while what this does is that it shows a code completion tooltip with suggestions - it doesn't actually change the code. That's different to auto_brace_complete which you modeled it after, which after inserts braces automatically.

I'd suggest maybe code_complete_enabled, which I'm not fully happy with either but it matches code_complete_delay so it's clear that the two are related.

While at it, could you add ,or_greater to the hint for code_complete_delay so that users who want it can extend the timer beyond 5 s if they wish so, as was done in #78284. I commented that it's not the right way to offer an opt out for the timer itself, but some people might want it longer than 5 s anyway.

[quinnyo]

I've made the suggested changes.

[akien-mga]

Two minor changes needed, but looks great otherwise.

[quinnyo]

Done and done!

(Not sure if I'll ever get used to in-class initialisers...)

[YuriSizov]

Sorry for the CI failure, it's not an issue with your code. But you need to do a rebase against master and force-push again.

[quinnyo]

Done!

[YuriSizov]

Sorry for a late review, but since this is configurable we should mention that this is only true by default.

Suggested change

	If [code]true[/code], code completion will be triggered automatically after [member text_editor/completion/code_complete_delay]. If [code]false[/code], you can still trigger completion manually by pressing [kbd]Ctrl + Space[/kbd] ([kbd]Cmd + Space[/kbd] on macOS).
	If [code]true[/code], code completion will be triggered automatically after [member text_editor/completion/code_complete_delay]. If [code]false[/code], you can still trigger completion with a shortcut (by default, [kbd]Ctrl + Space[/kbd] on Linux and Windows, [kbd]Cmd + Space[/kbd] on macOS).