LibRegex: Parse capture group names according to the ECMA262 spec

Author: https://github.com/davidot
Commit: 154ed3994c
Pull-request: https://github.com/SerenityOS/serenity/pull/11316
Reviewed-by: https://github.com/alimpfard
Reviewed-by: https://github.com/linusg ✅

Tests/LibRegex/Regex.cpp

@@ -593,6 +593,12 @@ TEST_CASE(ECMA262_parse)
         { "a{9007199254740992,9007199254740992}"sv, regex::Error::InvalidBraceContent },
         { "(?<a>a)(?<a>b)"sv, regex::Error::DuplicateNamedCapture },
         { "(?<a>a)(?<b>b)(?<a>c)"sv, regex::Error::DuplicateNamedCapture },
+        { "(?<1a>a)"sv, regex::Error::InvalidNameForCaptureGroup },
+        { "(?<\\a>a)"sv, regex::Error::InvalidNameForCaptureGroup },
+        { "(?<\ta>a)"sv, regex::Error::InvalidNameForCaptureGroup },
+        { "(?<$$_$$>a)"sv },
+        { "(?<ÿ>a)"sv },
+        { "(?<𝓑𝓻𝓸𝔀𝓷>a)"sv },
     };
 
     for (auto& test : tests) {