[ty] Avoid duplicate syntax errors for `await` outside functions
Summary
--
This PR fixes astral-sh/ty#2598 by not emitting the `YieldOutsideFunction`
syntax error for `await` expressions outside of functions. This isn't the most
elegant fix, but as I noted in the TODO comment, I think a better long-term fix
like not emitting `YieldOutsideFunction` errors for `await` at all would change
the behavior of Ruff's stable `F704` lint rule. We should be able to fix that
and this TODO when resolving #19122.
Test Plan
--
We already had an existing mdtest for this behavior, so I just had to update it
to remove the less specific error message
[ty] Add ParamSpec context to missing argument diagnostics
When a ParamSpec callable is called without the required `*args` or
`**kwargs`, the error message now includes a sub-diagnostic explaining
why these arguments are required. This addresses reviewer feedback
from PR #22820 about making it clearer why these parameters are
required in some cases and not in others.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>