[red-knot] Store starred-expression annotation types (#14106)

## Summary

- Store the expression type for annotations that are starred expressions
(see [discussion
here](https://github.com/astral-sh/ruff/pull/14091#discussion_r1828332857))
- Use `self.store_expression_type(…)` consistently throughout, as it
makes sure that no double-insertion errors occur.

closes #14115

## Test Plan

Added an invalid-syntax example to the corpus which leads to a panic on
`main`. Also added a Markdown test with a valid-syntax example that
would lead to a panic once we implement function parameter inference.

---------

Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>

crates/red_knot_python_semantic/resources/mdtest/annotations/starred_expressions.md

@@ -0,0 +1,18 @@
+# Starred expression annotations
+
+Type annotations for `*args` can be starred expressions themselves:
+
+```py
+from typing_extensions import TypeVarTuple
+
+Ts = TypeVarTuple("Ts")
+
+def append_int(*args: *Ts) -> tuple[*Ts, int]:
+    # TODO: should show some representation of the variadic generic type
+    reveal_type(args)  # revealed: @Todo
+
+    return (*args, 1)
+
+# TODO should be tuple[Literal[True], Literal["a"], int]
+reveal_type(append_int(True, "a"))  # revealed: @Todo
+```