Looks like the javalang parser doesn't handle some newer syntax.
For now just catch the errors. Long term we probably need to switch
to a different parser.
This enables us to generate documentation for more bean properties,
although a number of beans have javadoc on initializer code blocks which
makes it hard to access. This affects javadoc and IDE contextual
documentation too so should probably be fixed in the source code itself.
This is meant to complement the javadoc by providing a reference
more suitable for users trying to configure crawls rather than
developers writing new modules.
The doc generation could still do with some improving and some of the
source javadoc comments need fixing up but this is already useful so I'm
committing what I have so far.