Improve namedtuple definition (#2506)
Improve namedtuple definition (#2506)

While working on https://github.com/python/mypy/pull/11206 I found that `Regspec` definition is not ideal.
It is recommended to use the same string name, as variable name. 
For example, it affects how `pickle` works.

Related https://github.com/trailofbits/manticore/pull/2501
Related https://github.com/trailofbits/manticore/commit/6e036f3034b76bbecf36b5469e49294e038ff705
trailofbits/manticore,trailofbits/manticore,trailofbits/manticore