Add support for properly interpreting `context.selectedCompletionInfo`

[spew]

When vscode shows a popup Completion item (i.e. what they used to call intellisense: a regular language syntax or function that vscode knows about), any inline completion is supposed to start with the Completion item. That is to say, the completion item should be added to the end of the prefix. Take the following python example:

file_path = '/tmp/my-file'
with open(file_path, "r") as handle:
   # imagine the developer is in the middle of typing the period below
   obj = json.
   if obj.myField:
       print('my field is present')

So imagine the developer is typing the . in the line obj = json., vscode will pop up possible completions for json, and likely the method loads will be the top completion. The prefix that is sent to the LLM should use a value of obj = json.loads for that line. The suffix that comes after should also be included as normal.

The range that should be returned for the vscode.InlineCompletionItem should be properly adjusted for this as well. However, this portion is probably not related to this project.

[McPatate]

Hi @spew, you should open an issue in https://github.com/huggingface/llm-vscode, we'll deal with it there.

Thanks for reporting!

[spew]

I don't think llm-vscode can properly handle it without some help from this project.

[spew]

Created https://github.com/huggingface/llm-vscode/issues/127