Unify enums used for internal representation of quoting style

[AlexWaygood]

Summary

Currently we have four enums across the codebase for representing the fact that Python strings can either use single quotes (') or double quotes ("):

ruff/crates/ruff_python_ast/src/str.rs

Lines 6 to 13 in c269c1a

	#[derive(Debug, Default, Copy, Clone, Hash, PartialEq, Eq, is_macro::Is)]
	pub enum QuoteStyle {
	/// E.g. '
	Single,
	/// E.g. "
	#[default]
	Double,
	}

ruff/crates/ruff_python_formatter/src/string/mod.rs

Lines 234 to 242 in c269c1a

	/// The quotation character used to quote a string, byte, or fstring literal.
	#[derive(Copy, Clone, Debug, Eq, PartialEq)]
	pub enum QuoteChar {
	/// A single quote: `'`
	Single,
	/// A double quote: '"'
	Double,
	}

ruff/crates/ruff_python_codegen/src/stylist.rs

Lines 97 to 103 in c269c1a

	/// The quotation style used in Python source code.
	#[derive(Debug, Default, PartialEq, Eq, Copy, Clone)]
	pub enum Quote {
	Single,
	#[default]
	Double,
	}

ruff/crates/ruff_python_literal/src/escape.rs

Lines 1 to 5 in c269c1a

	#[derive(Debug, PartialEq, Eq, Copy, Clone, Hash, is_macro::Is)]
	pub enum Quote {
	Single,
	Double,
	}

This means we have a lot of impl From<QuoteEnum> for IdenticalOtherQuoteEnum methods, and it's generally somewhat confusing to keep track of the subtle differences between them. This PR unfies them into one enum in ruff_python_ast::str::QuoteStyle.

Using ruff_python_ast::str::QuoteStyle in the formatter would have created an awkward name clash with ruff_python_formatter::options::QuoteStyle, so I renamed ruff_python_formatter::options::QuoteStyle to ruff_python_formatter::options::QuotePreference. This seemed to me to more accurately reflect what that enum was for, but an alternative here would have been to rename ruff_python_ast::str::QuoteStyle. (Yet another alternative would be to always use the fully qualified name of ruff_python_ast::str:QuoteStyle in the formatter crate, but that felt too cumbersome to me.)

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.

[dhruvmanila]

Using ruff_python_ast::str::QuoteStyle in the formatter would have created an awkward name clash with ruff_python_ast::options::QuoteStyle, so I renamed ruff_python_ast::options::QuoteStyle to ruff_python_ast::options::QuotePreference.

Another option would be to use ruff_python_ast::str::Quote and keep the ruff_python_formatter::options::QuoteStyle. There's a chance that I might get confused with QuoteStyle's value coming from the quote-style config option 😅. This would mean that the enum usage would be Quote::Single, Quote::Double, quote.is_single, quote.is_double, etc. What do you think? @AlexWaygood

[AlexWaygood]

here's a chance that I might get confused with QuoteStyle's value coming from the quote-style config option 😅. This would mean that the enum usage would be Quote::Single, Quote::Double, quote.is_single, quote.is_double, etc. What do you think? @AlexWaygood

Ahh, that makes sense... I should have checked what the config option was called, sorry!

I'll change the formatter enum's name back, and change the ruff_python_ast enum to Quote 👍

[dhruvmanila]

This is great! So many lines red lines :)

[dhruvmanila]

Oh nice, I like this change as the current_expressions start with innermost f-string in case of nested f-strings.