[clang-tidy] Add override to overridden functions

See
https://clang.llvm.org/extra/clang-tidy/checks/modernize-use-override.html
for more on this warning.

Bug: v8:10488
Change-Id: I904fa4fada2860938a32be9f0a84af091adc76ca
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2211193Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Commit-Queue: Zhi An Ng <zhin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67989}

src/torque/ls/message.h

@@ -82,8 +82,8 @@ class Message : public BaseJsonAccessor {
   JSON_STRING_ACCESSORS(jsonrpc)
 
  protected:
-  const JsonObject& object() const { return value_.ToObject(); }
-  JsonObject& object() { return value_.ToObject(); }
+  const JsonObject& object() const override { return value_.ToObject(); }
+  JsonObject& object() override { return value_.ToObject(); }
 
  private:
   JsonValue value_;
@@ -96,8 +96,8 @@ class NestedJsonAccessor : public BaseJsonAccessor {
  public:
   explicit NestedJsonAccessor(JsonObject& object) : object_(object) {}
 
-  const JsonObject& object() const { return object_; }
-  JsonObject& object() { return object_; }
+  const JsonObject& object() const override { return object_; }
+  JsonObject& object() override { return object_; }
 
  private:
   JsonObject& object_;