markdown: enable autowriteall for markdown files

- Enables `autowriteall` for markdown files (pandoc filteype, as I use
  the vim-pandoc plugin).
- Modify the rules to ignore spell files.

Co-Authored-by: iGor milhit <igor@milhit.ch>

.gitignore

@@ -6,7 +6,7 @@ autoload
 .netrwhist
 
 # spell *.spl
-spell/
+spell/*
 
 tags
 test.sh

after/ftplugin/pandoc.lua

@@ -0,0 +1,6 @@
+-- Specific settings for markdown files (pandoc filetype)
+--  Enable the autowrite feature for all commands
+--  See :h awa
+
+vim.opt.awa=true
+vim.opt.colorcolumn=""