Fix anchors in links to Docker CLI build page (#282)

Anchors used to reference specific parts in
https://docs.docker.com/engine/reference/commandline/build/ no longer
exist. This commit fixes the links to reference existing anchors.

_implementors/json_reference.md

@@ -47,8 +47,8 @@ The focus of `devcontainer.json` is to describe how to enrich a container for th
 | `image` | string | **Required** when using an image. The name of an image in a container registry ([DockerHub](https://hub.docker.com), [GitHub Container Registry](https://docs.github.com/packages/guides/about-github-container-registry), [Azure Container Registry](https://azure.microsoft.com/services/container-registry/)) that `devcontainer.json` supporting services / tools should use to create the dev container. |
 | `build.dockerfile` | string |**Required** when using a Dockerfile. The location of a [Dockerfile](https://docs.docker.com/engine/reference/builder/) that defines the contents of the container. The path is relative to the `devcontainer.json` file. |
 | `build.context` | string | Path that the Docker build should be run from relative to `devcontainer.json`. For example, a value of `".."` would allow you to reference content in sibling directories. Defaults to `"."`. |
-| `build.args` | Object | A set of name-value pairs containing [Docker image build arguments](https://docs.docker.com/engine/reference/commandline/build/#set-build-time-variables---build-arg) that should be passed when building a Dockerfile.  Environment and [pre-defined variables](#variables-in-devcontainerjson) may be referenced in the values. Defaults to not set. For example: `"build": { "args": { "MYARG": "MYVALUE", "MYARGFROMENVVAR": "${localEnv:VARIABLE_NAME}" } }` |
-| `build.target` | string | A string that specifies a [Docker image build target](https://docs.docker.com/engine/reference/commandline/build/#specifying-target-build-stage---target) that should be passed when building a Dockerfile. Defaults to not set. For example: `"build": { "target": "development" }` |
+| `build.args` | Object | A set of name-value pairs containing [Docker image build arguments](https://docs.docker.com/engine/reference/commandline/build/#build-arg) that should be passed when building a Dockerfile.  Environment and [pre-defined variables](#variables-in-devcontainerjson) may be referenced in the values. Defaults to not set. For example: `"build": { "args": { "MYARG": "MYVALUE", "MYARGFROMENVVAR": "${localEnv:VARIABLE_NAME}" } }` |
+| `build.target` | string | A string that specifies a [Docker image build target](https://docs.docker.com/engine/reference/commandline/build/#target) that should be passed when building a Dockerfile. Defaults to not set. For example: `"build": { "target": "development" }` |
 | `build.cacheFrom` | string,<br>array | A string or array of strings that specify one or more images to use as caches when building the image. Cached image identifiers are passed to the `docker build` command with `--cache-from`. |
 | `appPort` | integer,<br>string,<br>array |  In most cases, we recommend using the new [forwardPorts property](#general-properties). This property accepts a port or array of ports that should be published locally when the container is running.Unlike `forwardPorts`, your application may need to listen on all interfaces (`0.0.0.0`) not just `localhost` for it to be available externally. Defaults to `[]`.<br>Learn more about publishing vs forwarding ports [here](#publishing-vs-forwarding-ports).<br>Note that the array syntax will execute the command without a shell. You can [learn more](#formatting-string-vs-array-properties) about formatting string vs array properties. |
 | `workspaceMount` | string | Requires `workspaceFolder` be set as well. Overrides the default local mount point for the workspace when the container is created. Supports the same values as the [Docker CLI `--mount` flag](https://docs.docker.com/engine/reference/commandline/run/#mount). Environment and [pre-defined variables](#variables-in-devcontainerjson) may be referenced in the value. For example: <br />`"workspaceMount": "source=${localWorkspaceFolder}/sub-folder,target=/workspace,type=bind,consistency=cached", "workspaceFolder": "/workspace"` |