Fix gdscript language server auto completion compatibility with external text editors.

[igordreher]

The gdscript language server changes the content of insertText during resolve.
But, by the lsp specs, that should not happen, as pointed out godotengine/godot-vscode-plugin#142 (comment) (his emphasis):

The request can only delay the computation of the detail and documentation properties. Other properties like sortText, filterText, insertText, textEdit and additionalTextEdits must be provided in the textDocument/completion response and must not be changed during resolve.

Because of this, bugs in external text editors regarding auto completion happen.
By removing the changes to insertText in the language server, this commit ensures better compatibility with external editors.

This commit removes the parenthesis addition to functions in auto complete. This feature should exist in the text editor and not in the language server.

Bugsquad edit:

• Fixes Language server string autocomplete place undesired quotes #48436
• Fixes Connect signal method adds parentheses godot-vscode-plugin#184
• Fixes Autocomplete in wrong format (extraneous quotes and parentheses added) godot-vscode-plugin#142
• Fixes Enabling type hints in editor adds extra bracket godot-vscode-plugin#323

[AaronRecord]

Does this happen to fix #48116, or is that a different issue?

[igordreher]

Does this happen to fix #48116, or is that a different issue?

I'm not sure, but I think that is a different issue.

[akien-mga]

CC @Razoric480

[kurtlachmann]

I disagree with the statement that this feature should be moved into the language client.
Adding parentheses to function calls is something that should definitely be the responsibility of the language server.
That is the whole point of a language server. The server should be the only implementation for autocompletion (towards which I'd count adding function parentheses since that is also the default behavior in the internal Godot editor).
A language client should only be responsible for inserting the text which it receives from the language server into its respective editor. If we say that this feature shouldn't be part of the language server then each client would be required to implement the logic independently which is exactly the problem the LSP was supposed to solve in the first place.

Also @igordreher said that "The gdscript language server changes the content of insertText during resolve." That's not really true. Or at least that's not the cause of the bugs. The insertText field is initialized in resolve. We could just as well move that block into the completion method which would make us compliant to the LSP specs. However that would not fix the bugs.

The problem is not that we're "changing the content of insertText". The problem is that the autocompletion in the language server is not behaving as expected. It's true that deleting these lines would fix the mentioned bugs. But I think in the long run they should instead be replaced by a better implementation.

[kurtlachmann]

I believe I found a better solution. See #59482

Note that neither this nor my own pull request would fix #48436 and godotengine/godot-vscode-plugin#142
Fixing the unwanted quotes is a more complex issue.

[igordreher]

If we say that this feature shouldn't be part of the language server then each client would be required to implement the logic independently which is exactly the problem the LSP was supposed to solve in the first place.

Good point.

As @kurtlachmann pointed out #49391 (comment),
this PR would only be a work around and not the correct approach.
And so, I'm closing this PR in favor of #59482