Problem: filetype: sway files are not recognized
Solution: detect '*.sw' files as sway filetype, include
a filetype plugin (Riley Bruins)
References:
https://github.com/FuelLabs/sway.
Comments taken from their syntax documentation. File extension taken
from the same documentation/GitHub's own recognition of these file types
closes: vim/vim#1597384b5b1c660
Co-authored-by: Riley Bruins <ribru17@hotmail.com>
