chore(doc): add Link to createParentChildLink doc (#14408)
chore(doc): add Link to createParentChildLink doc (#14408)

* add Link to createParentChildLink doc

* Update creating-a-source-plugin.md

ChristopherBiscardi/gatsby,gatsbyjs/gatsby,ChristopherBiscardi/gatsby,ChristopherBiscardi/gatsby,gatsbyjs/gatsby,gatsbyjs/gatsby,gatsbyjs/gatsby,gatsbyjs/gatsby,ChristopherBiscardi/gatsby,gatsbyjs/gatsby