docs: do not generate ref for internal serve command

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

docs/reference/buildx__INTERNAL_SERVE.md

@@ -1,13 +0,0 @@
-# docker buildx _INTERNAL_SERVE
-
-<!---MARKER_GEN_START-->
-### Options
-
-| Name        | Type     | Default | Description                              |
-|:------------|:---------|:--------|:-----------------------------------------|
-| `--builder` | `string` |         | Override the configured builder instance |
-| `--config`  | `string` |         | Specify buildx server config file        |
-
-
-<!---MARKER_GEN_END-->
-

hack/dockerfiles/docs.Dockerfile

@@ -22,6 +22,7 @@ rsync -a /context/. .
 docsgen --formats "$FORMATS" --source "docs/reference"
 mkdir /out
 cp -r docs/reference /out
+rm -f /out/reference/*__INTERNAL_SERVE.yaml /out/reference/*__INTERNAL_SERVE.md
 EOT
 
 FROM scratch AS update