Browser code missing named AbortController export

[wemeetagain]

browser.js is missing the AbortController named export.
The AbortController named export exists in src/abort-controller.ts (and browser.mjs), however, is missing in browser.js.
This results in an inconsistency. Code that successfully runs in nodejs throws an unexpected error when run in the browser.
Ex:

import {AbortController} from "abort-controller';
...

Typescript public interface includes an exported AbortController member, and popular convention is to use a named export if available (See this eslint-plugin-export rule). Thus, this issue will very likely affect direct consumers of this library, and worse, consumers further downstream, if consumers don't explicitly have browser tests!

This issue is for documentation purposes as several PRs implementing a fix are already open.
See: #22 and #29