doc: link PACKAGE_EXPORTS_RESOLVE to ESM section

Linked PACKAGE_EXPORTS_RESOLVE to "Resolver Algorithm Specification" in
"ECMAScript modules" page, so that the `require` pseudocode is easier to
understand.

PR-URL: https://github.com/nodejs/node/pull/37135


Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>