No real changes, just replace -1 with wxNOT_FOUND in wxBookCtrl code.

Make the code consistently use wxNOT_FOUND instead of -1 everywhere.

See #12622.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@65930 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/msw/notebook.h

@@ -86,7 +86,7 @@ public:
   virtual size_t GetPageCount() const;
 
     // set the currently selected page, return the index of the previously
-    // selected one (or -1 on error)
+    // selected one (or wxNOT_FOUND on error)
     // NB: this function will _not_ generate wxEVT_NOTEBOOK_PAGE_xxx events
   int SetSelection(size_t nPage);
     // get the currently selected page