docs: drop code references to local plan files

migrations/Version20260925120000.php

@@ -9,8 +9,7 @@ use Doctrine\Migrations\AbstractMigration;
 
 /**
  * What it takes to provision a teamer from a received application: the applicant's gender, and the
- * outcome of each of the three provisioning writes
- * (.ddev/plans/application-form-teamer-provisioning.md).
+ * outcome of each of the three provisioning writes.
  *
  * Emptying the table first is deliberate. gender is NOT NULL because BusPro refuses an address
  * without one and Teamer::$gender is not nullable either, and the existing rows predate the