[DOCS] Explicitly list **kwargs in QasmModule.unroll function arg / docstring

[ryanhill1]

The QasmModule.unroll() method currently just specifies **kwargs in it's function argument:

pyqasm/src/pyqasm/modules/base.py

Line 487 in 5a0c7b3

def unroll(self, **kwargs):

On the surface, this seems like a convenient short-hand because these kwargs will be passed directly to the QasmVisitor.__init__ method. However, from the API reference docs page, this isn't clear:

Since the unroll method is public facing, it would be good to document the available kwargs explicitly so that users don't have to dig through the source code to track the kwargs through to initialization of QasmVisitor.