Investigate needing watch=both for :Require

See [this comment](https://stackoverflow.com/questions/79238697/how-to-import-an-apl-namespace#comment139732699_79241385) which looks like it is happening on non-Windows, with Link defaulting to watch=ns and then `:Require` failing. However, I don't see why FSW has anything to do with `:Require`.

We should make sure `:Require` works to specify load ordering or document that it doesn't work and how to take care of internal dependencies.