docs, hide inflector comment targeting only contributors. [ci skip]

This is a follow up to: https://github.com/rails/rails/commit/07c70245a128cfe42f134be8759963dc98f1a63e

As suggested by @fxn this comment should not be visible in the API:
https://github.com/rails/rails/commit/07c70245a128cfe42f134be8759963dc98f1a63e#commitcomment-5331658