Merge remote-tracking branch 'mauro-exp/docbook3' into death-to-docbook

Mauro says:

This patch series convert the remaining DocBooks to ReST.

The first version was originally
send as 3 patch series:

   [PATCH 00/36] Convert DocBook documents to ReST
   [PATCH 0/5] Convert more books to ReST
   [PATCH 00/13] Get rid of DocBook

The lsm book was added as if it were a text file under
Documentation. The plan is to merge it with another file
under Documentation/security, after both this series and
a security Documentation patch series gets merged.

It also adjusts some Sphinx-pedantic errors/warnings on
some kernel-doc markups.

I also added some patches here to add PDF output for all
existing ReST books.

lib/Kconfig.debug

@@ -286,7 +286,7 @@ config DEBUG_FS
 	  write to these files.
 
 	  For detailed documentation on the debugfs API, see
-	  Documentation/DocBook/filesystems.
+	  Documentation/filesystems/.
 
 	  If unsure, say N.
 

lib/Kconfig.kgdb

@@ -13,7 +13,7 @@ menuconfig KGDB
 	  CONFIG_FRAME_POINTER to aid in producing more reliable stack
 	  backtraces in the external debugger.  Documentation of
 	  kernel debugger is available at http://kgdb.sourceforge.net
-	  as well as in DocBook form in Documentation/DocBook/.  If
+	  as well as in Documentation/dev-tools/kgdb.rst.  If
 	  unsure, say N.
 
 if KGDB