Add fish completion support (#4605)

main.go

@@ -29,6 +29,9 @@ var zshCompletion []byte
 //go:embed shell/key-bindings.fish
 var fishKeyBindings []byte
 
+//go:embed shell/completion.fish
+var fishCompletion []byte
+
 //go:embed man/man1/fzf.1
 var manPage []byte
 
@@ -65,7 +68,7 @@ func main() {
 	}
 	if options.Fish {
 		printScript("key-bindings.fish", fishKeyBindings)
-		fmt.Println("fzf_key_bindings")
+		printScript("completion.fish", fishCompletion)
 		return
 	}
 	if options.Help {