Documentation: use add-to-list and add trailing single quote

add-to-list is much shorter
\\' matches the empty string at the end of the string/buffer
Improve documentation for compile, preview, and export commands
Support for an external previewer or other open command
Document MacPorts Portfile
Add a function to renumber lists.
fixed some changes to the list cleanup code
goto the beginning of buffer before the renumbering lines
Fix `markdown--cleanup-list-numbers-level` freezing at the end of buffer
Document and bind list renumbering function

Make docstrings checkdoc-compliant.
Added menu item.
Bound to C-c C-c n.
Add a function to copy the output html snippet.
Kill ring save
add beginning and end of defun functions
Document defun navigation
Improve heading regexp used for imenu index creation

For atx-style headers, we should not include any leading or trailing
whitespace or trailing hashes.
Remove defun navigation functions

These are not working consisistently--some headings are being
skipped over--and we already have section navigation via
outline-minor-mode.
Improve markdown-regex-header and use for imenu

Avoids duplicate regex.
Support opening links with C-c C-o for inline URIs
Fix footnote location code in light of header regex changes

Adding the beginning of line anchor to `markdown-regex-header'
broke `markdown-footnote-text-find-new-location' in the case
where `markdown-footnote-location' was set to 'header.
markdown-mode 1.9
Don't declare local defun functions, which don't exist

It never fails, there's always something.  These should have been
removed in a929235, before the 1.9 release.