Re-enable the T and C linter prefix selectors

[charliermarsh]

Summary

In one of the prior refactors around lint rule prefixes, we removed the T and C selectors.

To take T as an example, the issue is that we have two "linters" that both use the T prefix -- flake8-debugger, whose rules are (e.g.) T100, and flake8-print, whose rules are (e.g.) T201. In the refactored model, flake8-debugger was represented as having a prefix of T10, and a rule under that prefix with code 0, which combines to an overall selector of T100.

Under this scheme, if the user provides the T prefix, we don't know where to map that code. Prior to this PR, it was redirected to T10, so if a user provided --select T, that aliased to --select T10, which enabled rule T100, thus ignoring the flake8-print rules entirely. I believe this was unintentional.

The same problem exists with the C prefix, where we have both the McCabe complexity and flake8-comprehensions rules. The McCabe rules no longer run under --select C, because it was redirected to C40.

This PR special-cases those two prefixes, introducing custom selectors for T and C to re-enable the expected user behavior.

Closes #3052.

[github-actions]

✅ ecosystem check detected no changes.

[charliermarsh]

No longer need to redirect these at all, since they have their own custom selectors.

[charliermarsh]

There are likely further refactors we can do here, but I'd like to get this out in the next release as it's probably surprising to users that certain codes are no longer enforced despite no change in their selectors (e.g., select = ["C"] no longer runs the complexity checks).