Clarify remote require of relative modules

Clarify remote require of relative modules

The docs for the `remote.require(module)` method were a little too terse for me to understand the behavior of relative module loading for `remote.require` and I had to run an experiment to understand the behavior (e.g. is the relative path relative to caller of `remote.require` or relative to some other path in the project related to the main process?).   I think this is correct but someone please double check my understanding.

Adding an example and additional explanation should help clarify this.  Feel free to edit the copy as needed.