Use simple wxEVT_SEARCH[_CANCEL] names for wxSearchCtrl events

The old wxEVT_SEARCHCTRL_{SEARCH,CANCEL}_BTN event names were unwieldy
and misleading because both of these events can be generated without
using the buttons, but by pressing Enter or Esc (the latter currently
works under macOS only, but this could change in the future).

interface/wx/srchctrl.h

@@ -35,19 +35,19 @@
     @endStyleTable
 
     @beginEventEmissionTable{wxCommandEvent}
-    To react to the changes in the control contents, use EVT_TEXT event, just
+    To react to the changes in the control contents, use wxEVT_TEXT event, just
     as you would do with wxTextCtrl. However it is recommended to use
-    EVT_SEARCHCTRL_SEARCH_BTN to actually start searching to avoid doing it too
-    soon, while the user is still typing (note that EVT_SEARCHCTRL_SEARCH_BTN
-    is also triggered by pressing Enter in the control).
-    @event{EVT_SEARCHCTRL_SEARCH_BTN(id, func)}
-        Respond to a @c wxEVT_SEARCHCTRL_SEARCH_BTN event, generated when the
+    wxEVT_SEARCH to actually start searching to avoid doing it too soon, while
+    the user is still typing (note that wxEVT_SEARCH is also triggered by
+    pressing Enter in the control).
+    @event{EVT_SEARCH(id, func)}
+        Respond to a @c wxEVT_SEARCH event, generated when the
         search button is clicked. Note that this does not initiate a search on
         its own, you need to perform the appropriate action in your event
         handler. You may use @code event.GetString() @endcode to retrieve the
         string to search for in the event handler code.
-    @event{EVT_SEARCHCTRL_CANCEL_BTN(id, func)}
-        Respond to a @c wxEVT_SEARCHCTRL_CANCEL_BTN event, generated when the
+    @event{EVT_SEARCH_CANCEL(id, func)}
+        Respond to a @c wxEVT_SEARCH_CANCEL event, generated when the
         cancel button is clicked.
     @endEventTable
 
@@ -161,5 +161,5 @@ public:
 };
 
 
-wxEventType  wxEVT_SEARCHCTRL_CANCEL_BTN;
-wxEventType  wxEVT_SEARCHCTRL_SEARCH_BTN;
+wxEventType  wxEVT_SEARCH_CANCEL;
+wxEventType  wxEVT_SEARCH;