Prefer the configured quote style

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## Summary

This PR extends the string formatting to respect the configured quote style.

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## Test Plan

Extended the string test with new cases and set it up to run twice: Once with the `quote_style: Doube`, and once with `quote_style: Single` single and double quotes. 

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crates/ruff_python_formatter/src/options.rs

@@ -109,7 +109,7 @@ impl QuoteStyle {
     }
 
     #[must_use]
-    pub const fn opposite(self) -> QuoteStyle {
+    pub const fn invert(self) -> QuoteStyle {
         match self {
             QuoteStyle::Single => QuoteStyle::Double,
             QuoteStyle::Double => QuoteStyle::Single,