first round, connecting overviews properly to main page

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@52042 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

docs/doxygen/overviews/thread.h

@@ -8,11 +8,12 @@
 
 /*!
 
- @page thread_overview Multithreading overview
+ @page overview_thread Multithreading overview
 
  Classes: #wxThread, #wxMutex,
  #wxCriticalSection,
  #wxCondition
+
  wxWidgets provides a complete set of classes encapsulating objects necessary in
  multithreaded (MT) programs: the #thread class itself and different
  synchronization objects: #mutexes and
@@ -21,6 +22,7 @@
  POSIX1.c threads API (a.k.a. pthreads), although several functions have
  different names and some features inspired by Win32 thread API are there as
  well.
+
  These classes will hopefully make writing MT programs easier and they also
  provide some extra error checking (compared to the native (be it Win32 or Posix)
  thread API), however it is still a non-trivial undertaking especially for large
@@ -35,6 +37,7 @@
  @ref idleevent_overview or even simply do everything at once
  but call wxWindow::Update() periodically to update
  the screen.
+
  If you do decide to use threads in your application, it is strongly recommended
  that no more than one thread calls GUI functions. The thread sample shows that
  it @e is possible for many different threads to call GUI functions at once
@@ -44,6 +47,7 @@
  more robust and will undoubtedly save you countless problems (example: under
  Win32 a thread can only access GDI objects such as pens, brushes, c created by
  itself and not by the other threads).
+
  For communication between secondary threads and the main thread, you may use
  wxEvtHandler::AddPendingEvent
  or its short version #wxPostEvent. These functions