The method wrapper used |*a, &b| which swallows kwargs in Ruby 3,
breaking methods that accept keyword arguments. Now uses |*a, **kw, &b|.

Also separates NameError (method doesn't exist) from other errors
during method aliasing for clearer error messages, and removes
Ruby 1.8/1.9 compatibility guards.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>