Fix return type of GetInternalEventEmitter

Changed the return type of KeyboardMonitor::GetInternalEventEmitter to EventEmitter<KeyboardEvent>& for type correctness and consistency with its declaration.

Author: lijy91

src/keyboard_monitor.h

@@ -45,7 +45,7 @@ class KeyboardMonitor : public EventEmitter<KeyboardEvent> {
   bool IsMonitoring() const;
 
   // Get access to the event emitter for internal use
-  EventEmitter& GetInternalEventEmitter();
+  EventEmitter<KeyboardEvent>& GetInternalEventEmitter();
 
  private:
   class Impl;

src/platform/windows/keyboard_monitor_windows.cpp

@@ -123,7 +123,7 @@ bool KeyboardMonitor::IsMonitoring() const {
   return impl_->hook_ != nullptr;
 }
 
-EventEmitter& KeyboardMonitor::GetInternalEventEmitter() {
+EventEmitter<KeyboardEvent>& KeyboardMonitor::GetInternalEventEmitter() {
   return *this;
 }