Improve handling of `/Include/` statements

[monkeydom]

• allows includes to work that are relative to the current file
• makes the language server return an URL to goto definition that works again

[monkeydom]

If you like this contribution then might I suggest a release? Being able to use your release binaries is helpful to us.

Also not sure if I need to fix the clippy as it is in unrelated existing code. Please advise.

[Schottkyc137]

Thanks of this improvement!