Use backticks for code in red-knot messages

[charliermarsh]

Summary

...and remove periods from messages that don't span more than a single sentence.

This is more consistent with how we present user-facing messages in uv (which has a defined style guide).

[charliermarsh]

I might also suggest removing periods from the end of these error messages (unless they span more than one sentence). We use that policy in uv and in Ruff.

[carljm]

Thanks!

I have no problem with removing final periods, in this PR or another one; it makes sense to have a consistent style guide across projects.

[carljm]

Looks like there's one missed test to fix.

[charliermarsh]

Sounds good. I'll probably just bundle it here then to reduce churn (fewer commits to ignore when git blaming).

[github-actions]

ruff-ecosystem results

Linter (stable)

✅ ecosystem check detected no linter changes.

Linter (preview)

✅ ecosystem check detected no linter changes.

Formatter (stable)

✅ ecosystem check detected no format changes.

Formatter (preview)

✅ ecosystem check detected no format changes.