visread docs link is dead

[trq5014]

The link to the visread docs from https://mpol-dev.github.io/ is not working. It sends you to https://visread.readthedocs.io/ and from my knowledge we no longer use read the docs. This is minor, but I figured I would bring it to attention.

[iancze]

Ah yea, that's a good catch. The new link is https://mpol-dev.github.io/visread/