ps:scale UX could be improved

[jdx]

from @ryanbrainard:

drive by CLI feedback: I was just trying to scale an app using the CLI and realized it’s rather unintuitive how to do it. In particular, the `Cannot update to more than 1 Hobby size dynos per process type.` message is not actionable at all. Inline help didn’t help much either. I ended up going to devcenter to figure out what i needed to do, but seems like something the says to do something like `h dyno:type standard-1x` would help folks out (and probably help get people to upgrade)
also confusing, it seems like the `dyno:type` command and `ps:scale` are very conflated and seem to basically do the same things
and `heroku scale --help` doesn’t work, but `heroku ps:scale --help` does
all little minor things, but it just made it a frustrating experience for something so simple