meta: remove collaborator self-nomination

Anyone with sufficient involvement in Node.js such that becoming a
collaborator would benefit Node.js, is going to have plenty of people to
ask. The self-nomination process has been entirely superfluous the
entire time I've been involved in Node.js. Simplify things and get rid
of it.

Author: Trott

GOVERNANCE.md

@@ -194,10 +194,6 @@ nominee publicly accepts it. In the case
 of an objection, the TSC is responsible for working with the individuals
 involved and finding a resolution.
 
-Collaborators might overlook someone with valuable contributions. In that case,
-the contributor may open an issue or contact a collaborator to request a
-nomination.
-
 #### How to review a collaborator nomination
 
 A collaborator nomination can be reviewed in the same way one would review a PR