Per UX review of help text, this commit makes several changes over the breadth
of the Faces help:

* Preface API-only action summaries/descriptions with "API only." (issue #7775)
* Provide both CLI and API info in "returns," with the CLI info first. (issue #7778)
* Summaries should be sentences. (Add punctuation.)
* First sentences of descriptions should reiterate summaries. (Summaries and
  descriptions should be displayed far enough apart that this isn't a problem.)
* Standardize on "subcommand" instead of "face" when talking about the entity
  you invoke at the command line. (Use "face" when describing API use.)
* Fix outdated or clunky text in several faces.

Faces help output relies on input from the documentation methods in each
of the faces to be documented. This commit calls those methods in each of our
faces, with varying levels of detail depending on their complexity.

The patch from issue #7221 permits indented heredocs. This patch takes advantage
of that to make the doc strings less messy.

This patch adds documentation strings to most of the faces, actions, and options
introduced in 2.7.0. There are a small number of TK notes remaining, and longer strings
have not been indented to take advantage of the patch from issue #7221.

Now that we have unified things, stop using the compatibility name in favour
of the new :console name for the output format.  No functional effect beyond
avoiding a deprecated output mode.

Reviewed-By: Jacob Helwig <jacob@puppetlabs.com>

This extends the catalog select action to be able to return more than a single
type, as well as supporting both programmatic and human focused rendering of
the return value.

Reviewed-By: Daniel Pittman <daniel@puppetlabs.com>

After some discussion we decided that most uses of the Puppet Face
infrastructure were about single faces on their own, not about the collection,
and so we were better referring to Puppet::Face[...] in code.

This implements that by translating names and references in the Ruby code to
the new, s-less, name.