Remove the view command and the editor setting with it

`view` was the last user of `editor`, so leaving the setting behind would
have made it exactly what `gitkey` was until recently: documented,
parsed, and doing nothing. It is gone from the struct, the template, the
environment, `config -k` and the settings table.

Both names are free for aliases now, as `open` already was.

The tests that used `editor` as their example of a project-overridable
setting use `gitkey` instead, which is the same kind of thing and still
exists.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

main.go

@@ -145,7 +145,7 @@ func parseArgs() (int, string, bool) {
 	}
 	cls := map[string]int{
 		"clone": 2, "init": 2, "log": 2,
-		"push": 1, "pushremote": 1, "list": 1, "tag": 1, "archive": 1, "show": 1, "view": 1,
+		"push": 1, "pushremote": 1, "list": 1, "tag": 1, "archive": 1, "show": 1,
 		"pull": 1, "fetch": 1, "status": 1, "diff": 1, "overview": 1,
 		"config": 1, "count": 1, "login": 1, "cloneall": 1, "release": 1,
 	}