doc: add ~/.config/nvim/init.lua to man page

[JohnVillalovos]

Man page previously only mentioned ~/.config/nvim/init.vim

[JohnVillalovos]

With this the man page near the end will show:

FILES
       ~/.config/nvim/init.lua  User-local nvim Lua configuration file.

       ~/.config/nvim           User-local nvim configuration directory.  See also XDG_CONFIG_HOME.

       $VIM/sysinit.vim         System-global nvim configuration file.

       $VIM                     System-global nvim runtime directory.

[justinmk]

Replace the old one, rather than enumerating every possibility. Users can read :help config to see full details.

[JohnVillalovos]

Replace the old one, rather than enumerating every possibility. Users can read :help config to see full details.

Done.

[dundargoc]

Thank you for your contribution! We collect all small documentation fixes into a single pull request and merge it once it gets big enough: #28837