set spell when entering commit, and use ftplugin instead of autocmds

after/ftplugin/gitcommit.lua

@@ -0,0 +1,2 @@
+vim.cmd('set spell!')
+vim.cmd('startinsert | 1')

after/ftplugin/gitrebase.lua

@@ -0,0 +1 @@
+gitcommit.lua

lua/core/auto.lua

@@ -13,13 +13,6 @@ auto('TextYankPost', { -- highlight yanks
   end
 })
 
-auto('FileType', { -- start git messages in insert mode
-  group = 'bufcheck',
-  pattern = { 'gitcommit', 'gitrebase', },
-  desc = 'Start git messages in insert mode.',
-  command = 'startinsert | 1'
-})
-
 auto('BufRead', { -- return to last place
   pattern = '*',
   command = [[call setpos(".", getpos("'\""))]],