Improve the documentation of the projection gallery examples

[seisman]

Currently, in the gallery examples for GMT projection, the projection parameters are explained in a dense paragraph after the raw syntax. E.g. (https://www.pygmt.org/dev/projections/azim/azim_equidistant.html),

I feel the long paragraph is a little hard to scan quickly.

Suggestion

What about explaining the projection parameters within a small table or a compact list?

For example:

[yvonnefroehlich]

This approach sounds similar to what is already done in the GMT documentation, e.g., https://docs.generic-mapping-tools.org/dev/reference/map-projections.html#albers-conic-equal-area-projection-jb-jb. And I agree a list can make the projection information more compact.
I think we should still mention which parameters are optional, as probably not all users are familiar with the GMT syntax for writing the general structure of the input argument.