formatter bug: f-strings with triple quotes

[davidszotten]

the formatter is too conservative when making sure it doesn't try to escape quotes inside formatted values, and doesn't take into account triple quotes

input: f''' {""} '''
output: f''' {""} '''
expected: f""" {""} """

i expect

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

Lines 36 to 42 in 7e9023b

	Self::FString(f_string) => {
	if f_string.values.iter().any(|value| match value {
	Expr::FormattedValue(ast::ExprFormattedValue { range, .. }) => {
	let string_content = locator.slice(*range);
	string_content.contains(['"', '\''])
	}
	_ => false,

needs to be more sophisticated

[davidszotten]

it's been a while now (blocked on #6365 for a few weeks)
but iirc i made this slightly better in my "proper f-string formatting" poc https://github.com/davidszotten/ruff/pull/1/files#diff-9ae227f70699315433485961eb6bbeb9a45487857fbfebe473e926e71bc194f5R46