Way to get log axes with datashader dsshow and matplotlib

#### Is your feature request related to a problem? Please describe.
I cannot find a way to get dsshow to return the points with a log axis or convert them to a log axis with matplotlib.

#### Describe the solution you'd like
Better documentation with instructions or feature addition if it is not currently doable.

#### Describe alternatives you've considered
dsshow doesn't appear to be fully linked to other datashader functionality. Matplotlib controls do not work to manipulate the object returned by dsshow.

#### Additional context
I believe this doesn't depend on versions or any other context.

Start by reviewing the existing dsshow documentation and its matplotlib integration to determine whether logarithmic axes are already supported. Clarify whether the intended result is documentation or a feature addition, then consider the work complete when dsshow can be used with log axes or the supported procedure is documented.

Written by the indexing model from the issue text.