Brought up here: https://caddy.community/t/v2-how-do-i-selectively-rewrite-multiple-times/9854

Basically, this disallows extra args on the line after the matcher for route, handle, handle_errors and handle_path. For example, these are now errors:

route @foo bar {
	respond "Foo"
}

handle bar {
	respond "Foo"
}

This is purely an adapter change to be stricter so that users don't have args in their config that do nothing useful (like thinking some args act like a matcher).