Clarify which Terraform registry Gitea actually has

Gitea lists "Terraform" among its package registries, which reads as if
the provider could be published there. It stores remote state for the
http backend -- not modules, not providers.

.goreleaser.yml

@@ -1,8 +1,9 @@
 # Publishes provider binaries to a Gitea release.
 #
-# Gitea has no Terraform provider registry -- that protocol is not one of the
-# ~20 package types it implements -- so these archives are consumed through a
-# filesystem mirror instead. See "Installing" in the README.
+# These archives are consumed through a filesystem mirror, because Gitea cannot
+# serve the provider protocol. Its package registry list does include
+# "Terraform", but that one stores remote state for the `http` backend -- it is
+# neither a module nor a provider registry. See "Installing" in the README.
 #
 # The archive names follow HashiCorp's convention
 # (terraform-provider-NAME_VERSION_OS_ARCH.zip) because a filesystem mirror