Minor fixups from Peter K. Lee.

Minor fixups from Peter K. Lee.

* experimental/muse-xml.el (muse-xml-fixup-tables): Be slightly less
  restrictive with our end-of-table regexp.

* lisp/muse-docbook.el (muse-docbook-fixup-tables): Look for tgroup
  instead of start of table.  Be less restrictive with several of our
  regexps.

* lisp/muse-html.el: Patch from Peter K. Lee.
  (muse-html-prepare-buffer): Work around edge case where the "charset="
  part has already been appended to muse-html-meta-content-type.
  (muse-html-fixup-tables): Be slightly less restrictive with our
  end-of-table regexp.
git-archimport-id: mwolson@gnu.org--2005/muse--main--1.0--patch-199