Adds treesitter and biscuit plugins + tweak to sudo write

The two plugins were added along with relevant configuration for each

If in neovim and sudo_askpass isn't set, vim will display a warning if
WW is typed in command mode

.gitmodules

@@ -73,3 +73,9 @@
 [submodule "nvim/.config/nvim/pack/bundle/opt/lexima.vim"]
 	path = nvim/.config/nvim/pack/bundle/opt/lexima.vim
 	url = https://github.com/cohama/lexima.vim
+[submodule "nvim/.config/nvim/pack/bundle/nvim-biscuits"]
+	path = nvim/.config/nvim/pack/bundle/opt/nvim-biscuits
+	url = https://github.com/code-biscuits/nvim-biscuits
+[submodule "nvim/.config/nvim/pack/bundle/opt/nvim-treesitter"]
+	path = nvim/.config/nvim/pack/bundle/opt/nvim-treesitter
+	url = https://github.com/nvim-treesitter/nvim-treesitter

nvim/.config/nvim/after/plugin/biscuit.vim

@@ -0,0 +1 @@
+highlight BiscuitColor gui=italic

nvim/.config/nvim/init.vim

@@ -22,6 +22,8 @@ if has('packages')
 		packadd! deoplete-lsp
 		packadd! deoplete-notmuch
 		packadd! firenvim
+		packadd! nvim-treesitter
+		packadd! nvim-biscuits
 		lua <<EOF
 		if ( vim.lsp ~= nil ) then
 			vim.cmd "packadd! nvim-lspconfig"

nvim/.config/nvim/pack/bundle/opt/nvim-biscuits

@@ -0,0 +1 @@
+Subproject commit 15a0cb1273bd36d5a734210cdc3406fb4bcfb733

nvim/.config/nvim/pack/bundle/opt/nvim-treesitter

@@ -0,0 +1 @@
+Subproject commit a47df48e7d4232fd771f2537a4fb43f582c026c9

nvim/.config/nvim/plugin/biscuits.vim

@@ -0,0 +1,12 @@
+lua <<EOF
+require('nvim-biscuits').setup({
+  default_config = {
+    min_distance = 3,
+    prefix_string = "  "
+  },
+  show_on_start = true,
+  toggle_keybind = "<leader>cb"
+})
+
+EOF
+

nvim/.config/nvim/plugin/mappings.vim

@@ -85,6 +85,8 @@ nnoremap <leader>p :call mine#functions#proselint()<CR>
 if has('nvim')
 	if !empty($SUDO_ASKPASS)
 		cnoremap WW w !sudo -A tee % > /dev/null
+	else
+		cnoremap WW echo "SUDO_ASKPASS variable needs to be set"<cr>
 	endif
 else
 	cnoremap WW w !sudo tee % > /dev/null

nvim/.config/nvim/plugin/treesitter.vim

@@ -0,0 +1,11 @@
+lua <<EOF
+require'nvim-treesitter.configs'.setup {
+	ensure_installed = "all",
+	highlight = {
+		enable = true
+	},
+	indent = {
+		enable = true
+	}
+}
+EOF