nvim: after/ftplugin: Disable spell check for certain file types

Now that we enable spell check globally disable it for certain file
and buffer types like dirvish etc.

nvim/.config/nvim/after/ftplugin/diff.vim

@@ -1,3 +1,5 @@
+setlocal nospell
+
 " Jump to sections of diff
 nnoremap <buffer> [c ?^@@<CR>
 nnoremap <buffer> ]c /^@@<CR>

nvim/.config/nvim/after/ftplugin/dirvish.vim

@@ -1,4 +1,5 @@
 setlocal bufhidden=hide
+setlocal nospell
 
 nnoremap <buffer> <silent> yy "+yy<C-^>
 

nvim/.config/nvim/after/ftplugin/git.vim

@@ -1,3 +1,5 @@
+setlocal nospell
+
 nnoremap <buffer> <silent>q  :bwipeout!<CR>
 
 nnoremap <buffer> <Leader>gb :call git#git_branch_checkout()<CR>