Update docs for addition of transfer manager

Closing the HTTP connection requesting a push or pull will cancel the
push or pull. This behavior also applies to the CLI.

Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>

docs/reference/commandline/build.md

@@ -98,12 +98,9 @@ adding a `.dockerignore` file to that directory as well. For information on
 creating one, see the [.dockerignore file](../builder.md#dockerignore-file).
 
 If the Docker client loses connection to the daemon, the build is canceled.
-This happens if you interrupt the Docker client with `ctrl-c` or if the Docker
-client is killed for any reason.
-
-> **Note:**
-> Currently only the "run" phase of the build can be canceled until pull
-> cancellation is implemented).
+This happens if you interrupt the Docker client with `CTRL-c` or if the Docker
+client is killed for any reason. If the build initiated a pull which is still
+running at the time the build is cancelled, the pull is cancelled as well.
 
 ## Return code
 

docs/reference/commandline/pull.md

@@ -49,3 +49,6 @@ use `docker pull`:
     # manually specifies the path to the default Docker registry. This could
     # be replaced with the path to a local registry to pull from another source.
     # sudo docker pull myhub.com:8080/test-image
+
+Killing the `docker pull` process, for example by pressing `CTRL-c` while it is
+running in a terminal, will terminate the pull operation.

docs/reference/commandline/push.md

@@ -19,3 +19,6 @@ parent = "smn_cli"
 
 Use `docker push` to share your images to the [Docker Hub](https://hub.docker.com)
 registry or to a self-hosted one.
+
+Killing the `docker push` process, for example by pressing `CTRL-c` while it is
+running in a terminal, will terminate the push operation.