LSP: Fix autocomplete quote handling

[0x4448]

Fixes #48436

Updates to language server:

• Add missing context to CompletionParams so context can be used in the resolve function.
• Omit quotes in auto-complete suggestion if triggered with single or double quote.

I'm new to Godot and C++, but after poking around the code base a bit, I was able to get it working by making two changes:

1. CompletionParams has a new context member. It provided an implementation for load() to include that data, but not one for to_json(). So context was missing from the JSON and there's already code in GDScriptTextDocument::resolve() that depends on that. I added context to the JSON so it can be used in resolve().
2. Now that resolve() has the context, the current bug can be fixed. If the completion was triggered with a single or double quote, then there's already a quote (or a pair of quotes) in the external editor. The auto-complete suggestion should be returned without quotes.

Both changes are in language server classes, so this change should not break the built-in editor. I did a quick test to confirm that still returns quotes.

Again, I'm new to Godot and C++, so if I'm overlooking something obvious, please let me know and I'll try to fix it.

[adamscott]

It seems fine to me! I tested it and it works.

And thank you for this first contribution. It's clean and does the job. Good job!

Don't hesitate to join the developer chat, especially if you want to continue contributing to Godot! Happy to see you there!

[AThousandShips]

Please squash your commits into one, see here

[0x4448]

Please squash your commits into one, see here

I've squashed the revisions to resolve() into one commit. I can also squash the to_json() change, but since that also fixes other existing code, I thought that might be better in a separate commit.

[AThousandShips]

No need for two different commits here, the changes aren't significant enough

[akien-mga]

Thanks! And congrats for your first merged Godot contribution 🎉

[Andy608]

Hello, I'm a noob when it comes to this kind of stuff, but I was wondering if this fix is going to be merged into Godot 3.5 LTS? Just started working with Godot and I've noticed this bug present in the current 3.5.3 LTS version. Thanks!

[YuriSizov]

Cherry-picked for 4.1.3.