bolt's `get_resources` uses the `libexec/query_resources.rb` to retrieve
resources as json from the target nodes. Especially https://github.com/puppetlabs/bolt/blob/7dec6e49d66c7f9ae06088d46ee3330de0ed2fed/libexec/query_resources.rb#L71
causes `ResourceShims` to fail as they did not implement `to_json`.

This integration test models what `libexec/query_resources.rb` is doing.
The added `to_json(*)` method now passes this test, and - shown in manual
testing - works for bolt.

(maint) backport minor fixes from master to 1.6.x

This implements the changes specified in puppetlabs/puppet-specifications#141

> The text and examples have been inconsistent with how `desc` vs `docs`
> has been handled. This change fixes the text and examples to all show
> and require `desc`, but accept `docs` in places where we showed it
> previously.

…k-1.6.x

(maint) implement `desc`/`docs` fallback