Use simpler markup string for anchors.
* lisp/muse-docbook.el (muse-docbook-markup-strings): Use 'anchor instead
of 'begin-anchor and 'end-anchor.
* lisp/muse-latex.el (muse-latex-markup-strings): Ditto.
* lisp/muse-publish.el (muse-publish-markup-anchor): Ditto.
* lisp/muse-texinfo.el (muse-texinfo-markup-strings): Ditto.
* lisp/muse-xml-common.el (muse-xml-markup-anchor): Ditto.
* lisp/muse-xml.el (muse-xml-markup-strings): Ditto.
* lisp/muse-html.el (muse-html-insert-anchor, muse-html-markup-anchor):
Revert previous change, since muse-html-insert-contents needs
muse-html-insert-anchor.
git-archimport-id: mwolson@gnu.org--2005/muse--main--1.0--patch-319