check that learning objectives are phrased as statements using action words

[noramcgregor]

@mark-bell-tna Suggest just that first one "Understand Machine Learning as a subfield of AI and name two others" in your section could be re-written to replace "understand" with a more action oriented word (examples here: https://tips.uark.edu/using-blooms-taxonomy/)?

[noramcgregor]

@MikeTrizna Empty bullet point here https://carpentries-incubator.github.io/machine-learning-librarians-archivists/03-what-is-ml-good-at/index.html and instead of "know" maybe an action oriented word from the taxonomy like "give examples of" or something like that?

[noramcgregor]

The Introduction needs learning objectives, I'll write that one https://carpentries-incubator.github.io/machine-learning-librarians-archivists/aio/index.html