Extracts the name from a canonical dspec.
dspec
dspec-name dspec => name
A canonical dspec.
name
A dspec name.
The function dspec-name extracts the name from the canonical dspec dspec .
Note that for part classes this is a list starting with the primary name.
If dspec is not canonicalized, dspec-name signals an error.
dspec-name
dspec-class
