[vcpkg edit] with overlays

[gavinltomra]

Since the recommended method to doing custom changes (especially in manifest mode) these days is apparently to use port overlays rather than forking/direct editing, I was surprised to discover that vcpkg edit only ever edits the builtin port, ignoring any overlays.

In particular, in a manifest-mode working folder with a vcpkg-configuration.json file, I would expect it to use that to determine which existing overlay provides the port, and edit that directory instead of the base port. Or if there is no such overlay, to offer to create one by copying the current port (either from the builtin registry or an additional registry, as appropriate) -- or perhaps error out if there are multiple overlay directories so it's ambiguous.

Even in classic mode, I would expect that it should open the overlay port if --overlay-ports is specified on the command line and the named overlay exists in that directory -- only opening the builtin port if there is no such overlay. (Or would it make sense to offer to copy in that case too? Maybe that should be an additional parameter to indicate you're expecting to edit an overlay?)