[OE-core] [RFC PATCH 0/1] package.bbclass, task.bbclass: Allow doc-pkgs in EXTRA_IMAGE_FEATURES

[Jason Wessel]

This is an RFC because I am not entirely sure this is the right way to
fix this problem.  The problem specifically is that of getting the
doc-pkgs package group to work properly.  After getting a fix for
this, it will be possible to update the Yocto documentation to reflect
the working doc-pkgs IMAGE_FEATURE.

Testing shows that it works as desired, but it is not clear if there
is any architectural side effects.

Thanks,
Jason.