improve add_recessions about cmapplot

[matthewstern]

to do this I need to unpack a little bit more, and create an altered ggproto object for GeomRect that inherits data from the top-level command. See https://ggplot2-book.org/internals.html and Noel's work with last point highlighting.

[matthewstern]

ggproto for rectangles is established. This inherits primary dataframe and uses that to filter the recessions. I have not yet figured out how to inherit the type of data...I am not sure this is possible.

Next step is to use the same framework to build a ggproto for text. Should be relatively straightforward.

[matthewstern]

this is done. We may have to come back around to confirming fonts once theme_cmap is further along.