fix: Add two checks for common errors (#128)

[dlsnyder8]

Two errors plague users with verbose errors: Inappropriate names with servers who have Server Discovery enabled and when servers hit the maximum # of channels in category.

This pull request adds two checks to give users a more specific error message

Understandably, this check is not complete, however based on Discord's error messages, there should not be any HTTP errors that would intersect with this check, so it should be a good band-aid until Discord has more robust HTTP error codes.

Issue #128