Support snippet templates and add help snippets

Add `autocmd` to automatically expand the `_template` snippet on the
`BufNewFile` event, if the expansion fails because the `_template`
snippet does not exist for the current `filetype` undo the changes. Do
the same thing when the `filetype` changes to `help`, since these are
`text` files to begin with the first `autocmd` has no effect.

UltiSnips/help.snippets

@@ -0,0 +1,24 @@
+snippet _template "help file template"
+*`!p snip.rv = snip.fn`*	For Vim version 8.0	Last change: `!p
+from datetime import datetime
+snip.rv = datetime.now().strftime('%B %d, %Y')`
+
+$0
+
+ vim:tw=78:ts=8:ft=help:norl:
+endsnippet
+
+snippet s "help section"
+==============================================================================
+${1:1}. ${2:Section}`!p
+spaces = 78 - len(t[1]) - len(snip.basename) - (2 * len(t[2])) - 3
+snip.rv = spaces * ' ' + '*' + snip.basename + '-' + t[2].lower() + '*'`
+
+$0
+endsnippet
+
+snippet d "help detail"
+`!p spaces = 78 - len(t[1])
+snip.rv = spaces * ' '`*${1:}*
+$0
+endsnippet

autoload/snippet.vim

@@ -0,0 +1,16 @@
+" Description: Expand snippet on file creation.
+
+" Attempt to expand the _template snippet if this is a new file.
+" https://noahfrederick.com/log/vim-templates-with-ultisnips-and-projectionist
+function! snippet#template() abort
+  " Return if non-empty buffer or file exists.
+  if !(line('$') == 1 && getline('$') ==# '') || filereadable(expand('%'))
+    return
+  endif
+  " Attempt to expand the _template snippet.
+  execute "normal! i_template\<C-r>=UltiSnips#ExpandSnippet()\<CR>"
+  if g:ulti_expand_res == 0
+    " Expansions failed, undo insert.
+    silent! undo
+  endif
+endfunction

plugin/autocmds.vim

@@ -1,14 +1,17 @@
 augroup benieAugroup
-  " Clear all autocmd's in this group
   autocmd!
 
   " Reopening a file at last curson position
   au BufReadPost * if line("'\"") > 0 && line("'\"") <= line("$")
           \ | exe "normal! g'\"" | endif
 
-  " Highlight conflict markers in any filefile
+  " Highlight conflict markers in any filetype
-  au FileType * :call matchadd('Todo', '^\(<<<<<<<\||||||||\|=======\|>>>>>>>\)\s\ze.*$')
+  au FileType * call matchadd('Todo', '^\(<<<<<<<\||||||||\|=======\|>>>>>>>\)\s\ze.*$')
 
-  " Read template into buffer and send line 1 to the black hold register
+  " Read template into buffer then send line 1 to the black hold register
   au BufNewFile todo.md read ~/.vim/templates/skeleton.todo.md | 1delete _
+  " Attempt to expand snippet named `_template` if it exists
+  au BufNewFile * silent! call snippet#template()
+  " Do the same when filetype changes to help
+  au FileType help silent! call snippet#template()
 augroup END