Function fungi_lang::eval::proj_namespace_name

pub fn proj_namespace_name(n: NameTmVal) -> Option<NameTm>

project/pattern-match the name of namespace, defined as the sub-term M in the following nameterm (lambda) form:

 #x.[M, x]

where [M, x] is the binary name formed from uknown name x and M, the name of the "namespace".