Improve error message for use of 'await' in non-async context

[uhyo]

As suggested in #26586, this PR adds to such an error a related span which points to its enclosing (non-async) function.

Example

// test.ts
function foo() {
  await null;

  for await (const _ of []);
}

Previous behavior:

test.ts:2:3 - error TS1308: 'await' expression is only allowed within an async function.

2   await null;
    ~~~~~

test.ts:4:7 - error TS1103: A 'for-await-of' statement is only allowed within an async function or async generator.

4   for await (const _ of []);
        ~~~~~


Found 2 errors.

New behavior:

test.ts:2:3 - error TS1308: 'await' expression is only allowed within an async function.

2   await null;
    ~~~~~

  test.ts:1:10
    1 function foo() {
               ~~~
    Did you mean to mark this function as 'async'?

test.ts:4:7 - error TS1103: A 'for-await-of' statement is only allowed within an async function or async generator.

4   for await (const _ of []);
        ~~~~~

  test.ts:1:10
    1 function foo() {
               ~~~
    Did you mean to mark this function as 'async'?


Found 2 errors.

Fixes #26586