Support Artifact Watcher Function Argument Names

[Flipout50]

The code commented out below should work but it needs to be executed when the ProgramChangeRecord indicates a change to function argument names. Its current position isn't correct. Likely this is a subEventType of a function event, but the exact details need to be figured out so that this code can be called at the correct time.

libbs/libbs/decompilers/ghidra/hooks.py

Lines 100 to 104 in 33a0114

	# TODO: Fix argument name support
	#changed_arg = FunctionArgument(None, newValue, None, None)
	#header = FunctionHeader(None, None, args={None: changed_arg})
	#self._interface.function_header_changed(header)
	pass

As an additional note, on this line:

libbs/libbs/decompilers/ghidra/hooks.py

Line 102 in 33a0114

#header = FunctionHeader(None, None, args={None: changed_arg})

We can't use None as the key, it will require a real offset.