Clarified that proxy can be changed via an variable.

library/get_url

@@ -31,6 +31,12 @@ short_description: Downloads files from HTTP, HTTPS, or FTP to node
 description:
      - Downloads files from HTTP, HTTPS, or FTP to the remote server. The remote
        server I(must) have direct access to the remote resource.
+     - By default, if an environment variable C(<protocol>_proxy) is set on
+       the target host, requests will be sent through that proxy. This
+       behaviour can be overriden by setting a variable for this task
+       (see `setting the environment
+       <http://ansible.cc/docs/playbooks2.html#setting-the-environment-and-working-with-proxies>`_),
+       or by using the use_proxy option.
 version_added: "0.6"
 options:
   url:
@@ -58,9 +64,8 @@ options:
     aliases: [ "thirsty" ]
   use_proxy:
     description:
-      - By default, if an environment variable C(<protocol>_proxy) is set on
-        the target host, request will be sent through the proxy. To override
-        this behaviour, set C(use_proxy=no).
+      - if C(yes), it will no use a proxy, even if one is defined by
+        in an environment variable on the target hosts.
     required: false
     default: yes
     choices: [yes, no]