[DOCS] Explain matplotlib get_cmap function about colorcet HOT 3 CLOSED

Colorcet's colormaps are already available from Matplotlib's get_cmap, but prefixed with "cet_":

from matplotlib.cm import get_cmap
import colorcet

get_cmap("cet_fire")

<matplotlib.colors.LinearSegmentedColormap at 0x11d7c2c50>

from colorcet.

Interesting... I did not realize that was possible. Did I miss this in the docs?

from colorcet.

Third paragraph of http://colorcet.pyviz.org/user_guide/index mentions:

The same colormaps are also registered with matplotlib's string-based dictionary with the prefix cet_, making them available by name within various matplotlib functions (e.g. cet_linear_kryw_0_100_c71, cet_linear_kryw_0_100_c71_r, cet_fire, or cet_fire_r).

But it doesn't specifically mention get_cmap, so we'd happily accept a PR to explain it better. Basically, if you can think of how to make sure no one else misses it, please do! :-)

If you have enough time to make matplotlib and bokeh examples for the user guide, illustrating the various ways to use them, we'd love to have those too!

from colorcet.