GH-15: flag words as rare instead of bad in NeoVim

This change marks all words in all dictionaries as rare words so that
NeoVim highlights them as SpellRare instead of SpellBad.  This lets you
distinguish between wordy writing and normal misspellings, respectively.

In order for this to work, your NeoVim needs to be patched as follows:

  https://github.com/neovim/neovim/pull/2456

  https://groups.google.com/forum/#!topic/vim_dev/rPWOoR3ZgSA

See `:help spell-wordlist-format` for details about dictionary markings.

data-neovim/en/being.dic

@@ -0,0 +1,90 @@
+# forms of 'to be', to identify where an active verb might be better
+# http://darlingmionette.deviantart.com/art/Words-To-Avoid-152886782
+/encoding=utf-8
+I am/?
+I have been/?
+I have not been/?
+I haven't been/?
+I haven’t been/?
+I was/?
+I wasn't/?
+I wasn’t/?
+I'dn't've/?
+I'm/?
+I've been/?
+I've not been/?
+I’dn’t’ve/?
+I’m/?
+I’ve been/?
+I’ve not been/?
+ain't/?
+ain’t/?
+am/?
+are/?
+aren't/?
+aren’t/?
+been/?
+being/?
+has been/?
+has not been/?
+hasn't been/?
+hasn’t been/?
+have/?
+haven't/?
+haven’t/?
+is/?
+isn't/?
+isn’t/?
+shall/?
+they are/?
+they aren't/?
+they aren’t/?
+they have been/?
+they have not been/?
+they haven't been/?
+they haven’t been/?
+they were/?
+they weren't/?
+they weren’t/?
+they're/?
+they've been/?
+they've not been/?
+they’re/?
+they’ve been/?
+they’ve not been/?
+was/?
+wasn't/?
+wasn’t/?
+we are/?
+we aren't/?
+we aren’t/?
+we have been/?
+we have not been/?
+we haven't been/?
+we haven’t been/?
+we were/?
+we weren't/?
+we weren’t/?
+we've been/?
+we've not been/?
+were/?
+weren't/?
+weren’t/?
+we’ve been/?
+we’ve not been/?
+you are/?
+you aren't/?
+you aren’t/?
+you have been/?
+you have not been/?
+you haven't been/?
+you haven’t been/?
+you were/?
+you weren't/?
+you weren’t/?
+you're/?
+you've been/?
+you've not been/?
+you’re/?
+you’ve been/?
+you’ve not been/?