Use shared leading_quote implementation in ruff_python_formatter (#3396)

crates/ruff_python_stdlib/src/str.rs

@@ -1,6 +1,3 @@
-use once_cell::sync::Lazy;
-use regex::Regex;
-
 /// See: <https://docs.python.org/3/reference/lexical_analysis.html#string-and-bytes-literals>
 pub const TRIPLE_QUOTE_PREFIXES: &[&str] = &[
     "u\"\"\"", "u'''", "r\"\"\"", "r'''", "U\"\"\"", "U'''", "R\"\"\"", "R'''", "\"\"\"", "'''",
@@ -11,9 +8,6 @@ pub const SINGLE_QUOTE_PREFIXES: &[&str] = &[
 pub const TRIPLE_QUOTE_SUFFIXES: &[&str] = &["\"\"\"", "'''"];
 pub const SINGLE_QUOTE_SUFFIXES: &[&str] = &["\"", "'"];
 
-pub static STRING_QUOTE_PREFIX_REGEX: Lazy<Regex> =
-    Lazy::new(|| Regex::new(r#"^(?i)[urb]*['"](?P<raw>.*)['"]$"#).unwrap());
-
 pub fn is_lower(s: &str) -> bool {
     let mut cased = false;
     for c in s.chars() {