editor: Do not show inline completion if snippet is active

[mrnugget]

This avoids inline completions being shown (and overriding <tab> behavior) when a snippet is active and the user wants to go through snippet placeholders with <tab>.

Easy to reproduce:

Open a Rust file and use the tfn snippet to produce a test function. Delete the placeholder. Without the change here, the inline provider would suggest a function name. If you <tab>, you accept it, but then you can't <tab> into the function body.

With this change the inline completions are deactivated as long as a snippet is active.

Closes #19484

Release Notes:

• Fixed inline completions (Copilot, Supermaven, ...) taking over when a snippet completion was active. That resulted in tab not working to jump to the next placeholder in the snippet.

[kurtbuilds]

I was excited that this got posted to the Quality Week and wanted to offer to pair on fixing it, but you already finished it! 😄

[0x2CA]

I'm not sure it makes sense to disable it outright, which would lose the feature forever, in vscode you can use esc to cancel the inline completions and continue to tab to the next placeholder

[mrnugget]

I'm not sure it makes sense to disable it outright, which would lose the feature forever, in vscode you can use esc to cancel the inline completions and continue to tab to the next placeholder

What do you think about that @kurtbuilds? I think that makes, except in Vim mode it's kinda not working.

[0x2CA]

I'm not sure it makes sense to disable it outright, which would lose the feature forever, in vscode you can use esc to cancel the inline completions and continue to tab to the next placeholder

What do you think about that @kurtbuilds? I think that makes, except in Vim mode it's kinda not working.

In vim it would be cumbersome, and this is the problem I'm having right now, in vscode you need to esc to cancel theinline completions, but it puts vim into normal mode, and you need a to go into insertion mode, and then tab to the next placeholders.

These are not just inline issues, but also conflict auto-completion issues.

The vscode solution is to use enter as a confirmation during autocompletion