Start work on porting icat to Go

tools/cmd/tool/main.go

@@ -9,6 +9,7 @@ import (
 	"kitty/tools/cmd/at"
 	"kitty/tools/cmd/clipboard"
 	"kitty/tools/cmd/edit_in_kitty"
+	"kitty/tools/cmd/icat"
 	"kitty/tools/cmd/update_self"
 	"kitty/tools/tui"
 )
@@ -26,6 +27,8 @@ func KittyToolEntryPoints(root *cli.Command) {
 	edit_in_kitty.EntryPoint(root)
 	// clipboard
 	clipboard.EntryPoint(root)
+	// icat
+	icat.EntryPoint(root)
 	// __hold_till_enter__
 	root.AddSubCommand(&cli.Command{
 		Name:            "__hold_till_enter__",