Improve error message for unsupported default arguments

[CalMacCQ]

Consider the following example with a default boolean flag...

@guppy
def qft3(qs: array[qubit, 3], add_swap: bool=True) -> None:
    h(qs[0])
    crz(qs[2], qs[0], pi/2)
    crz(qs[2], qs[0], pi/4)
    h(qs[1])
    crz(qs[2], qs[0], pi/2)
    h(qs[2])

    if add_swap:
        mem_swap(0, 2)

Now if I call this function and only take the qubit array as input (leaving the flag as its True value)

qubits = array(qubit(), qubit(), qubit())
qft3(qubits) # boolean flag not specified

When I compile this function, I get the error message

Error: Not enough arguments (at <In [5]>:18:21)
   | 
16 |             controlled_u(measured[control_index], state)
17 |             
18 |     qft4_inv(measured)
   |                      ^ Missing argument (expected 2, got 1)

Note: Function signature is `(array[qubit, 4], bool) -> None`

Guppy compilation failed due to 1 previous error

I think Ideally it should point out that default function args are an unsupported feature rather than just saying that a function argument is missing.