Setting `&spellfile` from the modeline is not allowed and will result in
an `E523: not allowed here` error. Fix the updating of the file by
additionally having an autocommand on BufWinEnter (i.e. after the
modeline was read).
TODO: Also get rid of the error message when rereading the modeline (:e)
As I started to type on the international US layout I don't need any
extra bindings for special characters in vim.
Move the update of `spellfile` into xdg.vim, as it was the only
remaining body of `NewSpellLang()` and fits thematically.
Fix bug that when the XDG Base Directory variables are not set on
startup a directory "~" is created in $HOME instead of falling back to
the default values.
When TERM is not xterm-256color (for example in st or tmux) t_8f and
t_8b have to be set manually for colors to work.
Add XDG_CONFIG_HOME/vim to packpath so that plugins work.