`twitfetch.py` fetches the threads defined in `tweets.txt`, and
then the tmux.html has an example (will likely be made a macro
in the future)...

This causes issues w/ the atom blog as it puts html tags in the middle
of an html document where they shouldn't be..

The issue is that w/ mark'd sections, the anchors will be relative
to the imported doc and NOT the source document..  So the markdown
toc feature that adds anchors to header tags would create permanent
links that won't work in the long term.  This fixes them up.