fix(ruby): handle braces correctly inside regex character classes

- Add character class handling to prevent {} inside [] from being treated as interpolation
- Support escaped closing brackets (\]) within character classes
- Ensure quantifiers like {3} still work outside character classes
- Add test cases to verify edge cases are handled properly

Author: j-erasmus

src/languages/ruby.js

@@ -232,6 +232,14 @@ export default function(hljs) {
     contains: [
       hljs.BACKSLASH_ESCAPE,
       SUBST,
+      {
+        begin: /\[/,
+        end: /\]/,
+        contains: [
+          hljs.BACKSLASH_ESCAPE,
+          { begin: /\\./ }
+        ]
+      },
       {
         begin: /\{/, end: /\}/,
         contains: ['self', hljs.BACKSLASH_ESCAPE, SUBST],
@@ -241,10 +249,10 @@ export default function(hljs) {
     illegal: /\n/,
     variants: [
       { begin: /%r\{/, end: /\}[a-z]*/ },
-      { begin: '%r\\(', end: '\\)[a-z]*' },
-      { begin: '%r!', end: '![a-z]*' },
-      { begin: '%r\\[', end: '\\][a-z]*' },
-      { begin: '/', end: '/[a-z]*' }
+      { begin: /%r\(/, end: /\)[a-z]*/ },
+      { begin: /%r!/, end: /![a-z]*/ },
+      { begin: /%r\[/, end: /\][a-z]*/ },
+      { begin: /\//, end: /\/[a-z]*/ }
     ]
   };
 

test/markup/ruby/regexes.expect.txt

@@ -4,3 +4,8 @@ str =~ <span class="hljs-regexp">%r!foo|bar$!</span>
 str =~ <span class="hljs-regexp">%r[foo|bar$]</span>
 str =~ <span class="hljs-regexp">%r(\(foo|bar\)$)</span>
 str =~ <span class="hljs-regexp">%r{(\.{2}|\A/)}</span>
+str =~ <span class="hljs-regexp">/[{}]/</span>
+str =~ <span class="hljs-regexp">/[\]]/</span>
+str =~ <span class="hljs-regexp">/[a-z]{3}/</span>
+str =~ <span class="hljs-regexp">%r{[{}]+}</span>
+str =~ <span class="hljs-regexp">/<span class="hljs-subst">#{var}</span>[{}]/</span>

test/markup/ruby/regexes.txt

@@ -4,3 +4,8 @@ str =~ %r!foo|bar$!
 str =~ %r[foo|bar$]
 str =~ %r(\(foo|bar\)$)
 str =~ %r{(\.{2}|\A/)}
+str =~ /[{}]/
+str =~ /[\]]/
+str =~ /[a-z]{3}/
+str =~ %r{[{}]+}
+str =~ /#{var}[{}]/