Doctree documentation: make documentation more concise.
Don't put element "Details" into a separate subsection
but just after a short element definition.
Do not repeat descriptions from the "details" list
in plain text description.
+ Less overhead and less scrolling in both, source and HTML.
+ A longer free-text description can move below the "details"
field-list making it more prominent and the overall structure of
element sections more uniform.
git-svn-id: http://svn.code.sf.net/p/docutils/code/trunk@9673 929543f6-e4f2-0310-98a6-ba3bd3dd1d04