unquoting preformatted blocks after m4 processing

This file is copyright © 2004,2005,2006,2011 by Panu Kalliokoski and released under the stx2any license.

Preformatted blocks use comment markers to prevent macro processing within them. The comment markers are added in [impl.inline]. Here we remove the comment markers after m4 processing. Quotes within preformatted blocks are also turned back into real quotes. Note that this cannot look right in the formatted document; please take a look at the source.

s#`#`#g
s#'#'#g
s###g
s###g