Short names are not used for printing `Theorem`s

[brianhuffman]

When printing a Theorem value (e.g. something proved with prove_print) with the saw-script print command, the pretty-printer does not display the preferred short names for constants; instead it prints the fully-qualified URI form of all names.

We should fix this so that it displays the more readable short names.

This is closely related to #1277.

[sauclovian-g]

This was fixed by #2894.