Fix false positives for disallowNeverMatch option in regexp/no-dupe-disjunctions rule (#81)

Author: ota-meshi

lib/rules/no-dupe-disjunctions.ts

@@ -57,7 +57,10 @@ export default createRule("no-dupe-disjunctions", {
             while (parent) {
                 if (parent.type === "Alternative") {
                     const index = parent.elements.indexOf(target)
-                    return index < parent.elements.length - 1
+                    if (index < parent.elements.length - 1) {
+                        return true
+                    }
+                    return hasAfterPattern(parent.parent)
                 }
                 if (parent.type === "Quantifier") {
                     target = parent

tests/lib/rules/no-dupe-disjunctions.ts

@@ -11,6 +11,7 @@ const tester = new RuleTester({
 tester.run("no-dupe-disjunctions", rule as any, {
     valid: [
         ...[
+            String.raw`/^\s*(eslint-(?:en|dis)able)(?:\s+(\S|\S[\s\S]*\S))?\s*$/u`,
             `/a|b/`,
             `/(a|b)/`,
             `/(?:a|b)/`,