Features Suggestion

Feature description:
Add a new bracket plottable, similar to how arrows work already. This could be used to label ranges like so:

Spans do sort of serve this purpose, but they cannot be used for ranges that are not aligned with one of the two axes, or that do not extend infinitely in one axis. For example:

Code example: If applicable, use this space to demonstrate how you wish the new feature could be used in code.

I am still unsure how the user should specify which way around the bracket should be drawn, but otherwise it's simple.

plt.AddBracket(x1, y1, x2, y2, SOME_WAY_TO_INDICATE_ORIENTATION);