Type annotations for magma functions

[rkshthrmsh]

For magma functions, like the one in #1213, how would one provide type annotation?

# inside a circuit definition
out = m.Register(m.UInt[32])()
count = m.Register(m.UInt[8])()

config(out.I, count.O)
# end circuit definition

def config(reg: ???, count: ???):
    with m.when(count == 0):
        reg @= m.uint(1, 32)
    with m.elsewhen(count == 1):
        reg @= m.uint(5, 32)

[leonardt]

In general, magma values are instances of m.Type, so like this:

def config(reg: m.Type, count: m.Type):

In this case, we could be more precise and say

def config(reg: m.UInt[32], count:m.UInt[8]):

Since m.UInt (and it's parameterized versions) are subclass of m.Type