Add documentation linters to PhyslibAlpha.

[jstoobysmith]

Within Physlib, we have optional linters for documentation. These should be turned on and enforced strictly in PhyslibAlpha, given the other weaker controls on review that we have in place there. This task is really down to:

1. identifying what those documentation linters are
2. adapting them to PhyslibAlpha
3. making sure that they are turned on automatically in the GitHub workflow for PhyslibAlpha