Fix order of operands.

[Linda-Njau]

This PR addresses the issue described in issue #26 by correcting the order of operands in the JSON output. Previously, operands were extracted from the function clause, but this change extracts them from the right-hand side of the assembly clause. Additionally, non-operand inputs are now filtered out.

To properly match operands to their respective types, the structure of operands stored in the Hashtbl operands has been updated. The previous structure was a simple list of names:

WXTYPE: funct6, vm, vs2, rs1, vd

The new structure stores a list of tuples, each containing a name and its type value:

WXTYPE: (vd, regidx), (vs2, regidx), (rs1, regidx), (vm, bits(1))

From the example above note:

1. funct6, which is not an operand, is now correctly filtered out with this update.
2. The change of operand order.
3. The change of operand structure.

[Linda-Njau]

I have also renamed the function for more clarity.

• pre-filter to filter_non_operands
• extract to extract_operands
• extract_operands to extract_and_map_operands

[Linda-Njau]

@ThinkOpenly, I made the changes to address your comments.