s/after/priority/ for `FasterMorePowerfulMines.esp`.

If you load `FasterMorePowerfulMines.esp`, it's because you want
"faster, more powerful mines", so it should generally be allowed to
override other mods' changes to the records this mod is changing. Using
the `after` only allows it to override specific, named mods, whereas
using `priority` will let it "sink" below any conflicting mods.