Code cleanup.

2013-06-19  Didier Verna  <didier@didierverna.net>

	* src/doc/symbol.lisp (headline-function):
	(render-headline):  New functions.
	(document (macro-definition)):
	(document (accessor-definition)):
	(document (generic-accessor-definition)): Use it.
Code cleanup.

2013-06-19  Didier Verna  <didier@didierverna.net>

	* src/doc/symbol.lisp (render-varoid): Encapsulate the Texinfo
	macro to use, specified by a new KIND first argument.
	(document (macro-definition)):
	(document (special-definition)):
	(document (symbol-macro-definition)): Update accordingly.