Trigger rebuilds on both [web.watcher].watch_path (in the config but not wired up) and cargo's depinfo

[tekacs]

Hullo hullo – as described. In using build.rs with Dioxus, I found that there wasn't a way (any more) to get the watcher to rebuild on custom input paths.

I'm using rerun-if-changed – I first tried using watch_path, but it looks like that got un-wired in #3797. I also wired up support for directories in rerun-if-changed as well.