Create colors.mlx

[wschwanghart]

This adds a new matlab notebook about using color functions in TopoToolbox.

[wkearn]

Looks good! You can download and view the built pages from this build artifact:

https://github.com/wkearn/gallery/actions/runs/23239621760/artifacts/5982912080

The script is quite large (1MB). Does it have the outputs stored in it? If so, can you clear all the outputs? They will be regenerated by the build process, and it helps keep the repository size down.

There is also a small problem with the link to the colormaps directory. Is the link text set in monospaced font or does it have backwards ticks around it? This does not play well with Sphinx's reStructuredText markup for links which uses backwards ticks. I think this is probably a bug somewhere in Sphinx/nbsphinx, but for now can you rephrase that link text or remove the monospaced font?