Improve autodata docstring detection

Currently, if a variable (eg. a data dict MY_VARIABLE) is imported from a submodule to a parent module, and that an "autodata" pointing to the parent module's MY_VARIABLE is added to documentation, the initial MY_VARIABLE's docstrings (eg. "#: stuffs" is lost. It doesn't seem possible to add this docstring near the "from submodule import MY_VARIABLE).

Autodata "annotation" can be used to workaround this, but in this case the repr() of the variable (that I wanted to be in docs) doesn't appear anymore.

It would be nice for sphinx to follow imports and find the docstring of imported variables, or that it uses a force-injected "doc" one would put in such variables (I tried, it didn't work), or that there is a way to force a display of the repr() of a variable.

Start by reproducing the imported MY_VARIABLE case described in the issue, including an autodata entry for the parent module and the original #: docstring. Trace how autodata handles imported variables and repr() output; done requires an agreed behavior that preserves the variable documentation and/or representation, followed by regression coverage.