build-push: remove empty ${{ }} from the login step comment

.forgejo/workflows/build-push.yml

@@ -49,7 +49,6 @@ jobs:
 
     env:
       REGISTRY: https://${{ vars.REGISTRY_HOST }}
-      REGISTRY_TOKEN: ${{ secrets.REGISTRY_TOKEN }}
 
     steps:
       - uses: actions/checkout@v4
@@ -111,6 +110,8 @@ jobs:
 
       - name: Log in to the Forgejo registry
         if: steps.image.outputs.changed == 'true'
+        env:
+          REGISTRY_TOKEN: ${{ secrets.REGISTRY_TOKEN }}
         run: |
           # NOT secrets.GITHUB_TOKEN -- Forgejo's per-job auto-injected token can
           # never push to the container registry (a known Forgejo limitation,
@@ -130,7 +131,7 @@ jobs:
           # credential that was in fact valid. Strip first, echo never.
           #
           # The token also goes through the ENVIRONMENT rather than being
-          # interpolated into the script text. `${{ }}` is substituted before bash
+          # interpolated into the script text. An expression is substituted before bash
           # parses the line, so a value containing a quote or newline would change
           # the shape of the command itself rather than just its arguments.
           tok=$(printf '%s' "$REGISTRY_TOKEN" | tr -d ' \t\r\n')