Promote some rules to "always" fixable (#7840)
## Summary
This PR upgrades some rules from "sometimes" to "always" fixes, now that
we're getting ready to ship support in the CLI. The focus here was on
identifying rules for which the diagnostic itself is high-confidence,
and the fix itself is too (assuming that the diagnostic is correct).
This is _unlike_ rules that _may_ be a false positive, like those that
(e.g.) assume an object is a dictionary when you call `.values()` on it.
Specifically, I upgraded:
- A bunch of rules that only apply to `.pyi` files.
- Rules that rewrite deprecated imports or aliases.
- Some other misc. rules, like: `empty-print-string`, `unused-noqa`,
`getattr-with-constant`.
Open to feedback on any of these.
