fix(gatsby): Allow "gatsby-node" directory for Parcel Compilation

[graysonhicks]

Description

Since v4.9 Gatsby added TS support to top-level gatsby-* files. Users often used a gatsby-node directory to organize lifecycle hooks, which were then imported in to gatsby-* files. An unintended regression of the Parcel compiling code was that gatsby-node directories were marked as misnamed (meant to catch issues like gatsby-node.tsx) with this error:

This error is extra confusing because the user does have a gatsby-node.js/ts file.

Users encountered this on minor upgrades from < 4.9 to > 4.9 if they had a gatsby-node directory.

Documentation

Documentation is here and shouldn't have to change.