Integrate optional plotting capabilities into ashist()

[willcollins10]

Description

This PR integrates optional plotting capabilities directly into the ashist() function. Users can now generate plots ('bar', 'line', or 'step') by setting the plot parameter to True and customize plot appearance using plot_kwargs.

Changes Made

• Added plot and plot_kwargs parameters to the ashist() function.
• Implemented plotting logic using matplotlib.pyplot based on the specified plot type.
• Automatically sets axis labels and plot titles using metadata attributes.
• Adds vertical lines for bin edges if bin_edges is True.

Testing

• Added unit tests to validate different plot types and plot_kwargs.
• Ensured that invalid plot types raise appropriate errors.
• Verified interaction with existing parameters like density and bin_edges.

Related Issues

Closes #<606>

[nwlandry]

@willcollins10 --- thanks for the PR! I will try to take a look this afternoon!

[nwlandry]

@willcollins10 --- side note, the tests fail because the example you added in the docstring never defines H.

[nwlandry]

Overall looks awesome! Three main comments: (1) move the plotting contents to a helper function and (2) add the ability to plot a scatterplot, and (3) fix the docstring so that the doctests pass. Thanks for the contribution!

[maximelucas]

@nwlandry I think I addressed your comments, if you're happy we can close.