Previously, it was necessary to document every payload field, link,
path parameter, or request. If an item was not documented a failure
would occur. This has proven to be too restrictive for some use cases,
for example splitting up the documentation of a payload’s fields. While
it was possible to use a preprocessor to modify the operation prior to
documentation to remove the items that should not be documented, this
was more difficult than it needed to be.
This commit adds support for marking a descriptor as ignored. Ignored
descriptors count when checking that everything has been documented but
do not actually appear in the generated documentation.
Closes gh-143