Filter out RELEASE_ROOT from PATH instead of running a login shell

[giddie]

For anyone running the LSP in a dev container or otherwise simplified environment, we cannot rely on the presence of SHELL or the behaviour of a login shell to provide a clean PATH. I propose we instead filter out the RELEASE_ROOT from PATH, which seems to adequately address the issue of using the correct paths for ASDF/mise.

[github-actions]

Hey there and thank you for opening this pull request! 👋🏼

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feat(engine): add new completions styles
bug: correctly index project symbols

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[mhanberg]

Would you be able to point me to documentation as to how the RELEASE_ROOT variable works and what it does?