Version Control With Subversion Source

and related markup") use <refsynopsisdiv> throughout the references.

* en/book/ref-reposhooks.xml,
* en/book/ref-svn.xml,
* en/book/ref-svnadmin.xml,
* en/book/ref-svndumpfilter.xml,
* en/book/ref-svnlook.xml,
* en/book/ref-svnmucc.xml,
* en/book/ref-svnrdump.xml,
* en/book/ref-svnserve.xml,
* en/book/ref-svnsync.xml,
* en/book/ref-svnversion.xml
Use <refsynopsisdiv> throughout instead of a hardcoded <refsect1>
with a <title>. While here, consistify formatting of the reference
entry front matter sections and divider comments.