Minor whitespace enhancement for some block-level tags
* lisp/muse-html.el (muse-html-src-tag): Pass end to
muse-publish-ensure-block.
* lisp/muse-journal.el (muse-journal-qotd-tag): Pass end to
muse-publish-ensure-block.
* lisp/muse-publish.el (muse-publish-ensure-block): Accept optional `end'
argument. Update documentation. Make sure that beg and end are placed
on blank lines.
(muse-publish-verse-tag, muse-publish-example-tag): Pass end to
muse-publish-ensure-block.
git-archimport-id: mwolson@gnu.org--2006/muse--main--1.0--patch-405