Attribute syntax should not specialize to built-in language attributes.

The inclusion of attributes within syntax creates unnecessary duplication and, furthermore, increases grammar footprint for no reason at all (similar to why people do not include function overloads inside grammar).

We are already at harm by this- the last consensus of attribute syntax DID allow trailing commas (in consistency with elsewhere), but the change to make them part of grammar did not preserve this- and did so silently. (represents this syntax with a trailing additional rule- unnecessary convolution)

I consider this an editorial issue; the attribute overloads should be much better live in the table, and the context-dependent words listing can be just a plain list that enumerates.