Generate wxEVT_TEXT_ENTER for Enter key on Numpad too in wxMSW

Handle WXK_NUMPAD_ENTER in the same way as we already handle WXK_RETURN.

Closes #18504.

src/msw/textctrl.cpp

@@ -2075,6 +2075,7 @@ void wxTextCtrl::OnChar(wxKeyEvent& event)
     switch ( event.GetKeyCode() )
     {
         case WXK_RETURN:
+        case WXK_NUMPAD_ENTER:
             // Single line controls only get this key code if they have
             // wxTE_PROCESS_ENTER style, but multiline ones always get it
             // because they need it for themselves. However we shouldn't

src/msw/textentry.cpp

@@ -580,6 +580,7 @@ private:
         switch ( event.GetKeyCode() )
         {
             case WXK_RETURN:
+            case WXK_NUMPAD_ENTER:
                 if ( m_win->HasFlag(wxTE_PROCESS_ENTER) )
                     specialKey = true;
                 break;