nvim: Fix coc.nvim and install it automatically

Fix bug introduced in c0f7b43 that stopped the sourcing of coc.nvim in
neovim.
Add command to the dotbot installation config to install coc.nvim
automatically after pulling its submodule.

.config/vim/vimrc

@@ -1,7 +1,7 @@
 " Plugins ######################################################################
 " Auto completion
 " needs vim >= 8.1.1719 to support features like popup and text property.
-if (has('patch-8.1.1719'))
+if (has('patch-8.1.1719') || has('nvim'))
 	packadd! coc.nvim
 	source $XDG_CONFIG_HOME/vim/coc.nvim.vim
 endif

meta/install.conf.yaml

@@ -19,6 +19,11 @@
       description: Building stderred
       stdout: true
       stderr: true
+    -
+      command: cd .config/vim/pack/plugins/opt/coc.nvim && yarn install --frozen-lockfile
+      description: Installing coc.nvim
+      stdout: true
+      stderr: true
 - link:
     ~/.xinitrc:
         path: .xinitrc