Confusion about some variadic functions

[fingolfin]

Various functions in homalg are documented as having a fixed arity, but their implementation is actually variadic; e.g. HomalgScalarMatrix and HomalgDiagonalMatrix. It is unclear to me if the documentation is right and the implementation is just needlessly complex (and lax in that it accepts all kinds of malformed inputs or else produces strange errors for it); or whether the documentation is outdated. Or possibly a mixture of the above?