[clangd] Use override keyword to override the base class method, NFC

git-svn-id: https://llvm.org/svn/llvm-project/clang-tools-extra/trunk@371194 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/clangd/ParsedAST.cpp b/clangd/ParsedAST.cpp
index d3f9b8b..b9f27e6 100644
--- a/clangd/ParsedAST.cpp
+++ b/clangd/ParsedAST.cpp
@@ -110,9 +110,8 @@
                                  std::vector<SourceLocation> &MainFileMacroLocs)
       : SM(SM), MainFileMacroLocs(MainFileMacroLocs) {}
 
-  virtual void MacroExpands(const Token &MacroNameTok,
-                            const MacroDefinition &MD, SourceRange Range,
-                            const MacroArgs *Args) {
+  void MacroExpands(const Token &MacroNameTok, const MacroDefinition &MD,
+                    SourceRange Range, const MacroArgs *Args) override {
     SourceLocation L = MacroNameTok.getLocation();
     if (!L.isMacroID() && isInsideMainFile(L, SM))
       MainFileMacroLocs.push_back(L);