Improve wording of the unauthenticated media deprecation box (#1916)

changelogs/client_server/newsfragments/1916.clarification

@@ -0,0 +1 @@
+Improve wording of the unauthenticated media deprecation box. Contributed by @HarHarLinks.

content/client-server-api/modules/content_repo.md

@@ -49,8 +49,9 @@ mxc://<server-name>/<media-id>
 Clients can access the content repository using the following endpoints.
 
 {{% boxes/added-in-paragraph %}}
-{{< changed-in v="1.11" >}} Clients SHOULD NOT use the deprecated media endpoints
+{{< changed-in v="1.11" >}} A number of endpoints under the /_matrix/media hierarchy
-described below. Instead, they SHOULD use the new endpoints which require authentication.
+have been deprecated and replaced with new endpoints which require authentication.
+The deprecated endpoints are marked in the section below.
 {{% /boxes/added-in-paragraph %}}
 
 {{% boxes/warning %}}