Wire profiling docs into the documentation tree

Add the new profiling module pages to the Debugging and Profiling toctree.
The order places the main profiling.rst entry point first, followed by the
two profiler implementations, then pstats, and finally the deprecated profile
module last.

Author: pablogsal

Doc/library/debug.rst

@@ -15,6 +15,10 @@ intrusive debugging or patching.
    bdb.rst
    faulthandler.rst
    pdb.rst
+   profiling.rst
+   profiling-tracing.rst
+   profiling-sampling.rst
+   pstats.rst
    profile.rst
    timeit.rst
    trace.rst