doc: Convert the debugobjects DocBook template to sphinx

A couple of the most minor heading tweaks, otherwise no changes to the text
itself beyond the mechanical conversion.

Note that the inclusion of the kerneldoc comments from the source has never
worked, since exported symbols were asked for and none of those functions
are exported to modules.  It doesn't work here either :)

Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/DocBook/Makefile

@@ -12,7 +12,7 @@ DOCBOOKS := z8530book.xml  \
 	    kernel-api.xml filesystems.xml lsm.xml kgdb.xml \
 	    gadget.xml libata.xml mtdnand.xml librs.xml rapidio.xml \
 	    genericirq.xml s390-drivers.xml uio-howto.xml scsi.xml \
-	    80211.xml debugobjects.xml sh.xml regulator.xml \
+	    80211.xml sh.xml regulator.xml \
 	    tracepoint.xml w1.xml \
 	    writing_musb_glue_layer.xml crypto-API.xml iio.xml
 

Documentation/core-api/index.rst

 ======================
-Core-API Documentation
+Core API Documentation
 ======================
 
-Kernel and driver related documentation.
+This is the beginning of a manual for core kernel APIs.  The conversion
+(and writing!) of documents for this manual is much appreciated!
+
+Core utilities
+==============
 
 .. toctree::
    :maxdepth: 1
 
    workqueue
 
+Interfaces for kernel debugging
+===============================
+
+.. toctree::
+   :maxdepth: 1
+
+   debug-objects	      
+
 .. only::  subproject
 
    Indices