Simplify formatting of strings by using flags from the AST nodes

[AlexWaygood]

Summary

This PR simplifies the formatter by using the flags available on AST nodes, which were added in #10298 and refined in #10314. These can be used to query the quoting style and prefix used by a string. (Currently, we compute these by reparsing them from the source code.)

I was hoping this might lead to a speedup -- locally for me, it seems to be performance-neutral. It's (in my opinion) a nice simplification, anyway.

Each commit is atomic; the full test suite passes on each commit.

Test Plan

cargo test

[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.

[MichaReiser]

Nice. It allows us to delete quiet a lot of code.

There are two concerns:

• Using impl StringPart leads to monomorphization of not entirely trivial functions -> More generated code. I recommend extracting a struct that holds just the information we need to avoid this
• We should move StringKind out of the parser crate because I want to make ruff_python_formatter independent of the parser crate eventually. It should only depend on the ruff_python_ast and not be concerned about how the source file was parsed (that will happen in a caller crate).

[AlexWaygood]

Not sure if all this belongs in nodes.rs. ruff_python_ast::str.rs didn't feel right, though, since nodes.rs depends on str.rs (it would have created a circular dependency between the two files.

[AlexWaygood]

Thanks! I added a commit to move the relevant abstractions from ruff_python_parser to ruff_python_ast, and addressed your other comments

[MichaReiser]

Thank you