Return axis and plot from plotting function

It would be helpful if the plotting function return their axis and plot and maybe the colorbar, so that it is easier to modify after the fact.

For example, to current modify the title after it was created, you need to do access it by `fig.content[1].title`, where `fig.content[1]` is the axis for this example.

Start by locating the plotting function described in the issue and inspect how it creates the axis, plot, and optional colorbar. Update the function's public return value so callers can modify those objects directly, then verify that existing plotting behavior remains intact and that the returned objects support title changes without accessing fig.content.

Written by the indexing model from the issue text.