Set correct signature to callChild to fix ts compilation issue

[llgcode]

Fix ts compilation issue, so that projects using it compiled correctly when importing this module.

[papodaca]

I unfortunately don't have permission on this repo anymore, i've published this change on my personal fork: https://www.npmjs.com/package/node-diff3-wrapper (https://github.com/papodaca/node-diff3-wrapper)

[llgcode]

You mean https://www.npmjs.com/package/node-diff3-wrapper is "the official package" for this wrapper?
You may remove the old package or mark it as deprecated somewhere.

Thanks to accept my change, I've updated my import, it works fine now :-)