fix typos

Signed-off-by: allencloud <allen.sun@daocloud.io>

docs/reference/commandline/attach.md

@@ -51,7 +51,7 @@ foreground over a slow client connection. Instead, users should use the
 
 ## Override the detach sequence
 
-If you want, you can configure a override the Docker key sequence for detach.
+If you want, you can configure an override the Docker key sequence for detach.
 This is is useful if the Docker default sequence conflicts with key squence you
 use for other applications. There are two ways to defines a your own detach key
 sequence, as a per-container override or as a configuration property on  your

docs/reference/commandline/dockerd.md

@@ -587,9 +587,9 @@ system's list of trusted CAs instead of enabling `--insecure-registry`.
 
 Enabling `--disable-legacy-registry` forces a docker daemon to only interact with registries which support the V2 protocol.  Specifically, the daemon will not attempt `push`, `pull` and `login` to v1 registries.  The exception to this is `search` which can still be performed on v1 registries.
 
-## Running a Docker daemon behind a HTTPS_PROXY
+## Running a Docker daemon behind an HTTPS_PROXY
 
-When running inside a LAN that uses a `HTTPS` proxy, the Docker Hub
+When running inside a LAN that uses an `HTTPS` proxy, the Docker Hub
 certificates will be replaced by the proxy's certificates. These certificates
 need to be added to your Docker host's configuration:
 

docs/reference/commandline/pull.md

@@ -29,7 +29,7 @@ use `docker pull`.
 
 ## Proxy configuration
 
-If you are behind a HTTP proxy server, for example in corporate settings,
+If you are behind an HTTP proxy server, for example in corporate settings,
 before open a connect to registry, you may need to configure the Docker
 daemon's proxy settings, using the `HTTP_PROXY`, `HTTPS_PROXY`, and `NO_PROXY`
 environment variables. To set these environment variables on a host using