Add a rule for left part of assignment: it'll be helpful to add scope…

[calixteman]

…d_name_identifier (c++)

[calixteman]

My goal is to have this rule in c++ grammar:

    _assignment_left_expression: ($, original) => prec.right(PREC.ASSIGNMENT, choice(
      original,
      $.scoped_namespace_identifier,
    )),

[maxbrunsfeld]

This is a great idea. I rebased it and marked that rule as inline, so that its presence will not change the generated parser (but it can still be overridden in the C++ grammar).