Re: [PATCH] alias: restore support for simple dotted aliases

[Jonatan Holmgren <jonatan@jontes.page>]

That is a challenge we are going to have to consider. I think reserving
`command` is a worthwhile compromise, but obviously we cannot do that for
arbitrary future keys such as `help`, `hidden`, etc.

One possible compromise would be to reserve `command` and `alias-*`, as
neither seems very likely to exist in users' historical alias names.

A new namespace makes the most sense from a namespace-pollution point of
view, but I struggle to see that as good UX. Even a separate namespace
only for alias metadata would make more sense to me than moving aliases
entirely, since subsection aliases with just `command` will likely be 
far more common than any future metadata keys, but this is not something 
I see as a good solution either.