Slightly reformat EnableProofCheck() declarations

Keep the entire wxTextProofOptions argument on the same line.

Remove unnecessary WXUNUSED() in the declarations of the function in
wxMSW/wxGTK headers.

No real changes.

include/wx/gtk/textctrl.h

@@ -98,9 +98,10 @@ public:
 
 #if wxUSE_SPELLCHECK && defined(__WXGTK3__)
     // Use native spelling and grammar checking functions.
-    virtual bool EnableProofCheck(bool WXUNUSED(enable) = true,
-                                  const wxTextProofOptions& WXUNUSED(options) =
-                                  wxTextProofOptions()) wxOVERRIDE;
+    virtual bool EnableProofCheck(
+            bool enable = true,
+            const wxTextProofOptions& options = wxTextProofOptions()
+        ) wxOVERRIDE;
     virtual bool IsProofCheckEnabled() const wxOVERRIDE;
 #endif // wxUSE_SPELLCHECK && __WXGTK3__