docs: add anchor-tags for flags

This will generate "details_url" for options, so that the options
table on the pages at docs.docker.com link to the section describing
the option.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
(cherry picked from commit 2b976720f4)
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

docs/reference/commandline/stack_deploy.md

@@ -39,7 +39,7 @@ Create and update a stack from a `compose` file on the swarm.
 
 ## Examples
 
-### Compose file
+### <a name=compose-file></a> Compose file (--compose-file)
 
 The `deploy` command supports compose file version `3.0` and above.