Bug
For the js/ts:

/**
 * @param {|} x
 */
function foo(x) {}

quick suggestions currently not enabled when typing inside the jsdoc type annotation

Possible fix
My original proposed fix was adding a meta.embedded scope to the types: atom/language-javascript#539

It we can't get this fixed in language-javascript, we can add meta.embedded to our TS grammar specifically. I'll keep investigating other possible solutions as well