Use more descriptive error for lox proto functions

Request functions for protocols in the Lox library previously returned a ProofError error type, which is not verbose enough to allow for accurate debugging.

This commit introduces a new error enum, CredentialError, with several types that allow for descriptive error messages.

Closes #59 (closed)

assigned to @cohosh

requested review from @meskio

approved this merge request

LGTM

added 9 commits

• 1535539c...12deedde - 8 commits from branch tpo/anti-censorship:main
• 954633c2 - Use more descriptive error for lox proto functions

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added 2 commits

• bd584097 - 1 commit from branch tpo/anti-censorship:main
• c92a14d6 - Use more descriptive error for lox proto functions

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merged