Document control-flow requirements for never-returning calls

[Copilot]

Calls to explicitly never-returning methods do not affect control flow when an identifier in the call target has an inferred type.

• Document the explicit-type requirements for assertion and never-returning calls.
• Explain the circular control-flow analysis constraint.
• Show the required receiver annotation:

const impl: FooImpl = new FooImpl();

const f = (): number => {
    impl.bar(new Error());
};

• Fixes Typescript still checks return type in a lamba that calls a function returning 'never' #63714