Complex completion not applied if selected only using mouse

[dibarbet]

See also microsoft/vscode-dotnettools#1020 (comment)

When the complex completion item is selected from the list using the mouse (but not highlighted), the complex edit does not apply.

However, if the item is first highlighted via the keyboard, then selected via a mouse click, the complex edit applies.

[dibarbet]

@JoeRobich and I debugged this. The issue seems to be related to VSCode disposing of resolved completion items before the command is able to be invoked, when the item is clicked instead of selected.

Basically releaseCompletionItems gets called before _convertCompletionItem and so _convertCompletionItem throws.

This is only an issue for completion items where the command is only populated during resolve. While this is a VSCode side bug, I don't think we'll get much traction here as VSCode now indicates that modifiying the command in resolve is not supported:

2025-04-10 16:23:43.600 [warning] [Deprecation Warning] 'CompletionItem.command' is deprecated. extension MAY NOT change 'command' of a CompletionItem during resolve

Likely the approach we have to take here is to create a command upfront with no details on the complex text edit. The client side implementation of the command will have to instead call back to the server to retrieve the edits, and then apply them.