Problem: VimwikiTOC and follow_link do not support header (anchor) with
link in their body
Solution:
- VimwikiTOC (easy): Create function base.vim s:clean_header_text that
converts [DESC](URL) -> DESC
- follow_link (hard):
-- [[URL]]: was already working due to punctuation removal.
-- [DESC](URL): Search for a potential `]([^)]*)` after every character
69ead3bf3c
