vim-patch:9.1.0826: filetype: sway files are not recognized

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#15973

84b5b1c660

Co-authored-by: Riley Bruins <ribru17@hotmail.com>

runtime/lua/vim/filetype.lua

@@ -1151,6 +1151,7 @@ local extension = {
   sface = 'surface',
   svelte = 'svelte',
   svg = 'svg',
+  sw = 'sway',
   swift = 'swift',
   swiftinterface = 'swift',
   swig = 'swig',