Ensure correct usage of language IDs

[Yantrio]

There are currently 5 actions that are not using ilsp.ParseLanguageID which causes a language mismatch ("terraform" != "opentofu") and so some items are thrown away (For example, references).

This patch ensures that all references to the document's language ID also goes through ilsp.ParseLanguageID

Resolves #127

Checklist

• I have read the contribution guide.
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Go checklist

• I have run golangci-lint on my change and receive no errors relevant to my code.
• I have run existing tests to ensure my code doesn't break anything.
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[Gogotchuri]

Awesome! It appears to be the correct approach for the time being.
We might want to embed language ID evaluation into hcl-lang to ensure we treat "opentofu" and "terraform" the same.
I have mentioned somewhere before that this need for mapping stems from the fact that most editors have a single mapping for .tf files ("terraform"), and it will take a long time for all of them to also identify those files as "opentofu".

[diofeher]

Great stuff!