build(gha): move named contexts section to dedicated page

Signed-off-by: CrazyMax <crazy-max@users.noreply.github.com>

_data/toc.yaml

@@ -1627,6 +1627,8 @@ manuals:
             title: Local registry
           - path: /build/ci/github-actions/share-image-jobs/
             title: Share built image between jobs
+          - path: /build/ci/github-actions/named-contexts/
+            title: Named contexts
           - path: /build/ci/github-actions/examples/
             title: Examples
     - sectiontitle: Bake

build/ci/github-actions/examples.md

@@ -7,101 +7,7 @@ keywords: ci, github actions, gha, examples
 This page showcases different examples of how you can customize and use the
 Docker GitHub Actions in your CI pipelines.
 
-## Named contexts
 
-You can define [additional build contexts](../../../engine/reference/commandline/buildx_build.md#build-context),
-and access them in your Dockerfile with `FROM name` or `--from=name`. When
-Dockerfile defines a stage with the same name it's overwritten.
-
-This can be useful with GitHub Actions to reuse results from other builds or pin
-an image to a specific tag in your workflow.
-
-### Pin image to a tag
-
-Replace `alpine:latest` with a pinned one:
-
-```dockerfile
-# syntax=docker/dockerfile:1
-FROM alpine
-RUN echo "Hello World"
-```
-
-```yaml
-name: ci
-
-on:
-  push:
-    branches:
-      - "main"
-
-jobs:
-  docker:
-    runs-on: ubuntu-latest
-    steps:
-      -
-        name: Checkout
-        uses: actions/checkout@v3
-      -
-        name: Set up Docker Buildx
-        uses: docker/setup-buildx-action@v2
-      -
-        name: Build
-        uses: docker/build-push-action@v4
-        with:
-          context: .
-          build-contexts: |
-            alpine=docker-image://alpine:3.16
-          tags: myimage:latest
-```
-
-### Use image in subsequent steps
-
-By default, the [Docker Setup Buildx](https://github.com/marketplace/actions/docker-setup-buildx){:target="blank" rel="noopener" class=""}
-action uses `docker-container` as a build driver, so built Docker images aren't
-loaded automatically.
-
-With named contexts you can reuse the built image:
-
-```dockerfile
-# syntax=docker/dockerfile:1
-FROM alpine
-RUN echo "Hello World"
-```
-
-```yaml
-name: ci
-
-on:
-  push:
-    branches:
-      - "main"
-
-jobs:
-  docker:
-    runs-on: ubuntu-latest
-    steps:
-      -
-        name: Checkout
-        uses: actions/checkout@v3
-      -
-        name: Set up Docker Buildx
-        uses: docker/setup-buildx-action@v2
-      -
-        name: Build base image
-        uses: docker/build-push-action@v4
-        with:
-          context: base
-          load: true
-          tags: my-base-image:latest
-      -
-        name: Build
-        uses: docker/build-push-action@v4
-        with:
-          context: .
-          build-contexts: |
-            alpine=docker-image://my-base-image:latest
-          tags: myimage:latest
-```
 
 ## Copy images between registries
 

build/ci/github-actions/named-contexts.md

@@ -0,0 +1,102 @@
+---
+title: Named contexts with GitHub Actions
+keywords: ci, github actions, gha, buildkit, buildx, context
+---
+
+You can define [additional build contexts](../../../engine/reference/commandline/buildx_build.md#build-context),
+and access them in your Dockerfile with `FROM name` or `--from=name`. When
+Dockerfile defines a stage with the same name it's overwritten.
+
+This can be useful with GitHub Actions to reuse results from other builds or pin
+an image to a specific tag in your workflow.
+
+## Pin image to a tag
+
+Replace `alpine:latest` with a pinned one:
+
+```dockerfile
+# syntax=docker/dockerfile:1
+FROM alpine
+RUN echo "Hello World"
+```
+
+{% raw %}
+```yaml
+name: ci
+
+on:
+  push:
+    branches:
+      - "main"
+
+jobs:
+  docker:
+    runs-on: ubuntu-latest
+    steps:
+      -
+        name: Checkout
+        uses: actions/checkout@v3
+      -
+        name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v2
+      -
+        name: Build
+        uses: docker/build-push-action@v4
+        with:
+          context: .
+          build-contexts: |
+            alpine=docker-image://alpine:3.16
+          tags: myimage:latest
+```
+{% endraw %}
+
+## Use image in subsequent steps
+
+By default, the [Docker Setup Buildx](https://github.com/marketplace/actions/docker-setup-buildx){:target="blank" rel="noopener" class=""}
+action uses `docker-container` as a build driver, so built Docker images aren't
+loaded automatically.
+
+With named contexts you can reuse the built image:
+
+```dockerfile
+# syntax=docker/dockerfile:1
+FROM alpine
+RUN echo "Hello World"
+```
+
+{% raw %}
+```yaml
+name: ci
+
+on:
+  push:
+    branches:
+      - "main"
+
+jobs:
+  docker:
+    runs-on: ubuntu-latest
+    steps:
+      -
+        name: Checkout
+        uses: actions/checkout@v3
+      -
+        name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v2
+      -
+        name: Build base image
+        uses: docker/build-push-action@v4
+        with:
+          context: base
+          load: true
+          tags: my-base-image:latest
+      -
+        name: Build
+        uses: docker/build-push-action@v4
+        with:
+          context: .
+          build-contexts: |
+            alpine=docker-image://my-base-image:latest
+          tags: myimage:latest
+```
+{% endraw %}