Fix completions of exports elsewhere in same file

[andrewbranch]

Fixes #43289, along with another bug I found on the way:

module.exports = { a/**/ } // has a completion for itself

and

const c = 0;
export { c as something };
export * as somethingElse from "./other";

s/**/ // has completions for 'something' and 'somethingElse'

[andrewbranch]

@sandersn I realized I couldn’t really fix the primary bug (#43289) without addressing the contextual typing thing head-on, which I think I’ve done now. getContextualTypeForThisPropertyAssignment is now only used for this (and aliased-this) property assignments. We now group AssignmentDeclarationKind.ExportsProperty, .Prototype, .PrototypeProperty, and .ModuleExports together as being the simpler cases where they can have a contextual type only via a JSDoc type annotation, whereas .Property and .ThisProperty might be new declarations, might be immediately annotated with JSDoc, or might have a contextual type from the original declaration of the object/class. Some of the simpler cases were incorrectly being fed through that more complicated logic.

[andrewbranch]

@typescript-bot user test this

[typescript-bot]

Heya @andrewbranch, I've started to run the parallelized community code test suite on this PR at 61521db. You can monitor the build here.

[typescript-bot]

The user suite test run you requested has finished and failed. I've opened a PR with the baseline diff from master.

[sandersn]

switch scope rules are boooooooooo