Document logic behind `get_backend() == MAGIC_URI_THING`

[flying-sheep]

Would be great to have some comments to explain this:

plotting_api/src/plot.py

Lines 34 to 38 in 006d509

	if not ax_was_provided:
	if plt.get_backend() == "module://matplotlib_inline.backend_inline":
	plt.close()
	else:
	plt.show()