refactor: Harper-ls Error-Handling Improvements

[grantlemons]

This should make it easier to track issues in harper_ls. This changes appropriate functions to return anyhow::Results, and in functions that can't, the anyhow error is logged in a concise way. These functions also add context to the anyhow error to make it easier to trace.

Anyhow also ships with a macro bail!(), which simplifies forceable returns of new anyhow errors. For instance:

return Err(anyhow::format_err!("forceStable must be a boolean value."));

Becomes:

bail!("forceStable must be a boolean value.");

[elijah-potter]

I've got some pedantic things I'd like to see changed. Feel free to push back if you disagree.