[Clang-tidy] Fix Clang warning in misc/StringConstructorCheck.h.

Using LLVM_ENABLE_WARNINGS=ON is good idea.


git-svn-id: https://llvm.org/svn/llvm-project/clang-tools-extra/trunk@267228 91177308-0d34-0410-b5e6-96231b3b80d8

clang-tidy/misc/StringConstructorCheck.h

@@ -23,7 +23,7 @@ namespace misc {
 class StringConstructorCheck : public ClangTidyCheck {
 public:
   StringConstructorCheck(StringRef Name, ClangTidyContext *Context);
-  void storeOptions(ClangTidyOptions::OptionMap &Opts);
+  void storeOptions(ClangTidyOptions::OptionMap &Opts) override;
   void registerMatchers(ast_matchers::MatchFinder *Finder) override;
   void check(const ast_matchers::MatchFinder::MatchResult &Result) override;