This also fixes several issues where attribute arguments could not be
parsed as a TokenList since some of its arguments already had structure
and were not tokens
This commit starts to support syntax nodes for @ attributes list for
declarations. These attributes don't include modifiers like "static" or
access keywords. Along with the function change, the commit refactors
some existing code to reduce duplication.
* Generate libSyntax API
This patch removes the hand-rolled libSyntax API and replaces it with an
API that's entirely automatically generated. This means the API is
guaranteed to be internally stylistically and functionally consistent.
