Update fish completions

`--config` should autocomplete filepaths

Author: ammgws

completions/fish/sway.fish

@@ -2,7 +2,7 @@
 
 complete -f -c sway
 complete -c sway -s h -l help --description "Show help message and quit."
-complete -c sway -s c -l config --description "Specifies a config file."
+complete -c sway -s c -l config --description "Specifies a config file." -r
 complete -c sway -s C -l validate --description "Check the validity of the config file, then exit."
 complete -c sway -s d -l debug --description "Enables full logging, including debug information."
 complete -c sway -s v -l version --description "Show the version number and quit."