Can access per argument type comments

[AWhetter]

Description

Adds a new type_comment_args attribute to Arguments nodes so that per argument type comments can be accessed:

>>> import astroid
>>> func = astroid.extract_node('''
... def sum(
...         a,  # type: int
...         b,  # type: int
... ):
...     # type: (...) -> int
...     return a + b
... ''')
>>> func.args.type_comment_args
[<Name.int l.1 at 0x7ff60a46fd30>, <Name.int l.1 at 0x7ff60a46fda0>]

Type of Changes

	Type
✓	✨ New feature

Related Issue

Closes #665

[PCManticore]

Sweet, thanks @AWhetter !