Allow © in copyright notices (#10065)

Closes #10061.

crates/ruff/tests/snapshots/show_settings__display_default_settings.snap

@@ -232,7 +232,7 @@ linter.flake8_bandit.check_typed_exception = false
 linter.flake8_bugbear.extend_immutable_calls = []
 linter.flake8_builtins.builtins_ignorelist = []
 linter.flake8_comprehensions.allow_dict_calls_with_keyword_arguments = false
-linter.flake8_copyright.notice_rgx = (?i)Copyright\s+(\(C\)\s+)?\d{4}(-\d{4})*
+linter.flake8_copyright.notice_rgx = (?i)Copyright\s+((?:\(C\)|©)\s+)?\d{4}(-\d{4})*
 linter.flake8_copyright.author = none
 linter.flake8_copyright.min_file_size = 0
 linter.flake8_errmsg.max_string_length = 0

crates/ruff_linter/src/rules/flake8_copyright/mod.rs

@@ -29,6 +29,20 @@ import os
             r"
 # Copyright (C) 2023
 
+import os
+"
+            .trim(),
+            &settings::LinterSettings::for_rules(vec![Rule::MissingCopyrightNotice]),
+        );
+        assert_messages!(diagnostics);
+    }
+
+    #[test]
+    fn notice_with_unicode_c() {
+        let diagnostics = test_snippet(
+            r"
+# Copyright © 2023
+
 import os
 "
             .trim(),

crates/ruff_linter/src/rules/flake8_copyright/settings.rs

@@ -15,7 +15,7 @@ pub struct Settings {
 }
 
 pub static COPYRIGHT: Lazy<Regex> =
-    Lazy::new(|| Regex::new(r"(?i)Copyright\s+(\(C\)\s+)?\d{4}(-\d{4})*").unwrap());
+    Lazy::new(|| Regex::new(r"(?i)Copyright\s+((?:\(C\)|©)\s+)?\d{4}(-\d{4})*").unwrap());
 
 impl Default for Settings {
     fn default() -> Self {

crates/ruff_linter/src/rules/flake8_copyright/snapshots/ruff_linter__rules__flake8_copyright__tests__notice_with_unicode_c.snap

@@ -0,0 +1,4 @@
+---
+source: crates/ruff_linter/src/rules/flake8_copyright/mod.rs
+---
+

crates/ruff_workspace/src/options.rs

@@ -1123,14 +1123,14 @@ pub struct Flake8CopyrightOptions {
     /// The regular expression used to match the copyright notice, compiled
     /// with the [`regex`](https://docs.rs/regex/latest/regex/) crate.
     ///
-    /// Defaults to `(?i)Copyright\s+(\(C\)\s+)?\d{4}(-\d{4})*`, which matches
+    /// Defaults to `(?i)Copyright\s+((?:\(C\)|©)\s+)?\d{4}(-\d{4})*`, which matches
     /// the following:
     /// - `Copyright 2023`
     /// - `Copyright (C) 2023`
     /// - `Copyright 2021-2023`
     /// - `Copyright (C) 2021-2023`
     #[option(
-        default = r#"(?i)Copyright\s+(\(C\)\s+)?\d{4}([-,]\d{4})*"#,
+        default = r#"(?i)Copyright\s+((?:\(C\)|©)\s+)?\d{4}([-,]\d{4})*"#,
         value_type = "str",
         example = r#"notice-rgx = "(?i)Copyright \\(C\\) \\d{4}""#
     )]