Add missing semicolon to examples using wxDECLARE_XXX() macros

Such macros must be followed by semicolons but a couple of examples were
missing them.

Closes https://github.com/wxWidgets/wxWidgets/pull/1337

Closes #18408.

docs/doxygen/overviews/eventhandling.h

@@ -98,10 +98,11 @@ First define one or more <em>event handlers</em>. They
 are just simple methods of the class that take as a parameter a
 reference to an object of a wxEvent-derived class and have no return value (any
 return information is passed via the argument, which is why it is non-const).
-You also need to insert a macro
+You also need to insert a line with the macro indicating that the class uses an
+event table, like this:
 
 @code
-wxDECLARE_EVENT_TABLE()
+wxDECLARE_EVENT_TABLE();
 @endcode
 
 somewhere in the class declaration. It doesn't matter where it appears but
@@ -132,7 +133,7 @@ private:
     // obligation to do that; this one is an event handler too:
     void DoTest(wxCommandEvent& event);
 
-    wxDECLARE_EVENT_TABLE()
+    wxDECLARE_EVENT_TABLE();
 };
 @endcode
 

interface/wx/event.h

@@ -4799,7 +4799,7 @@ wxEventType wxNewEventType();
 
     This is mostly used by wxWidgets internally, e.g.
     @code
-    wxDECLARE_EXPORTED_EVENT(WXDLLIMPEXP_CORE, wxEVT_BUTTON, wxCommandEvent)
+    wxDECLARE_EXPORTED_EVENT(WXDLLIMPEXP_CORE, wxEVT_BUTTON, wxCommandEvent);
     @endcode
  */
 #define wxDECLARE_EXPORTED_EVENT( expdecl, name, cls ) \