Update lib.ts to support exports that start with $ and _

[nicksrandall]

This will detect exports that start with $ and _.

Here is a snippet from @lexical/html that was causing an issue for me:

exports.$generateHtmlFromNodes = $generateHtmlFromNodes;
exports.$generateNodesFromDOM = $generateNodesFromDOM;

The updated regex will correctly identify this module as common-js.

[nicksrandall]

Anything I can do to help this get merged?