Merge branch 'em/man-bold-literal'

The manpage output of our documentation did not render well in
terminal; typeset literals in bold by default to make them stand
out more.

* em/man-bold-literal:
  Documentation: bold literals in man

Documentation/Makefile

@@ -146,7 +146,7 @@ else
 	ASCIIDOC_EXTRA += -a git-asciidoc-no-roff
 	endif
 endif
-ifdef MAN_BOLD_LITERAL
+ifndef NO_MAN_BOLD_LITERAL
 XMLTO_EXTRA += -m manpage-bold-literal.xsl
 endif
 ifdef DOCBOOK_SUPPRESS_SP