common|synopsis.xsl: rename directive type=sections id generation

common|synopsis.xsl: rename directive type=sections id generation

This commits is a follow up of r1805189 and it is meant
to allow directives with the same name but different type
to coexist in the same document without triggering errors
while executing validate-xhtml.

For example: mod_md.xml recently introduced the following:

* ManagedDomain
* <ManagedDomain> (this one is type=section)

In my opinion this is a perfectly valid use case and it should
be allowed/handled correctly by the doc generation process/validation.

In order to avoid clashing the directive ids will get a suffix
called "section" if type=section will be present as param.

Quicklinks, <directive> links have been updated to the new
scheme to avoid dandling pointers in the doc.

Comments/reviews are welcome, if I left something behind
please let me know.

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1805193 13f79535-47bb-0310-9956-ffa450edef68