Is it possible to determine the available Category (aka DGM) extension classes
at runtime? I have been relying on DefaultGroovyMethods.DGM_LIKE_CLASSES, but
this has been getting reduced with each release due to modularization. And it
was never really a good source to begin with. I tried looking through
ExtensionModuleRegstry, but I couldn't make out a good entry point for asking
for the DGM classes. I see STC using this stuff to ask if a given method name
is a DGM. But this does not meet the needs of content assist, which must
suggest all method names for a given prefix.
