chore(hosts): drop redundant return {} from host lua files

require() only needs the module's side effects; the returned value is
ignored by hyprland.lua. Chester.lua and example.lua now match
Rutherford.lua in ending after their config statements.

hypr/hosts/Chester.lua

@@ -9,5 +9,3 @@ hl.monitor({
     position = "0x0",
     scale    = 1.5,
 })
-
-return {}

hypr/hosts/example.lua

@@ -6,5 +6,3 @@
 --
 -- To add your own machine, copy this to hosts/<your-hostname>.lua and fill it
 -- in. The hostname lookup strips any domain suffix (e.g. "laptop.home" -> "laptop").
-
-return {}