This commit changes the autocmd registration in vimwiki so that
registration happens once rather than once per extension.
Instead of the following,
autocmd BufEnter *.md call s:setup_buffer_enter()
autocmd BufEnter *.mdown call s:setup_buffer_enter()
We'll now only run,
autocmd BufEnter *.md,*.mdown call s:setup_buffer_enter()
This probably has no effect on performance but it makes for a simpler
implementation.
152a7bfdf1
