Naming of homomorphic split Wingman command

[santiweight]

The Homomorphic split command on Wingman, while making sense, is an opaque name to anyone less familiar with category theory etc. A potentially better option is for the Wingman command displayed to be based on the type of the functor in question. For example, if splitting on a variable "var" of type Either, the command might look like:

 Wingman: map var to Either

See #1582 for more discussion

[santiweight]

I'm not sure how to tag this as Wingman/improvement or assign to @isovector but we should do that :)

[isovector]

I'd like some other ideas for the naming scheme here. The major moving pieces here are the name of the variable and the type constructor in question. For each data constructor C of the type constructor, we want to construct a match of the form:

    C a b -> C _ _

[santiweight]

Another suggestion: "Wingman: map constructor fields"