update activity intros (github#27216)

Author: skedwards88

content/rest/activity/feeds.md

@@ -11,6 +11,10 @@ topics:
 miniTocMaxHeadingLevel: 3
 ---
 
+## About the Feeds API
+
+To see what feeds are available to you, use the [Get feeds](#get-feeds) operation. You can then get a feed by sending a request to one of the feed URLs.
+
 ### Example of getting an Atom feed
 
 To get a feed in Atom format, you must specify the `application/atom+xml` type in the `Accept` header. For example, to get the Atom feed for GitHub security advisories:

content/rest/activity/notifications.md

@@ -1,6 +1,6 @@
 ---
 title: Notifications
-intro: ''
+intro: 'The Notifications API lets you manage {% data variables.product.product_name %} notifications.'
 versions:
   fpt: '*'
   ghes: '*'
@@ -11,18 +11,9 @@ topics:
 miniTocMaxHeadingLevel: 3
 ---
 
-Users receive notifications for conversations in repositories they watch including:
+## About the Notifications API
 
-* Issues and their comments
-* Pull Requests and their comments
-* Comments on any commits
-
-Notifications are also sent for conversations in unwatched repositories when the user is involved including:
-
-* **@mentions**
-* Issue assignments
-* Commits the user authors or commits
-* Any discussion in which the user actively participates
+The Notifications API lets you manage {% data variables.product.product_name %} notifications. For more information about notifications, see "[About notifications](/account-and-profile/managing-subscriptions-and-notifications-on-github/setting-up-notifications/about-notifications)."
 
 All Notification API calls require the `notifications` or `repo` API scopes.  Doing this will give read-only access to some issue and commit content. You will still need the `repo` scope to access issues and commits from their respective endpoints.
 
@@ -44,11 +35,11 @@ $    -H "If-Modified-Since: Thu, 25 Oct 2012 15:16:27 GMT"
 > X-Poll-Interval: 60
 ```
 
-### Notification reasons
+### About notification reasons
 
 When retrieving responses from the Notifications API, each payload has a key titled `reason`. These correspond to events that trigger a notification.
 
-Here's a list of potential `reason`s for receiving a notification:
+These are the potential `reason`s for receiving a notification:
 
 Reason Name | Description
 ------------|------------

content/rest/activity/starring.md

@@ -1,6 +1,6 @@
 ---
 title: Starring
-intro: 'Repository starring is a feature that lets users bookmark repositories.'
+intro: 'The Starring API lets you bookmark a repository.'
 versions:
   fpt: '*'
   ghes: '*'
@@ -11,7 +11,9 @@ topics:
 miniTocMaxHeadingLevel: 3
 ---
 
-Stars are shown next to repositories to show an approximate level of interest. Stars have no effect on notifications or the activity feed.
+## About the Starring API
+
+The Starring API lets you bookmark a repository. Stars are shown next to repositories to show an approximate level of interest. Stars have no effect on notifications or the activity feed. For more information, see "[Saving repositories with stars](/get-started/exploring-projects-on-github/saving-repositories-with-stars)."
 
 ### Starring vs. Watching
 

content/rest/activity/watching.md

@@ -1,6 +1,6 @@
 ---
 title: Watching
-intro: "Watching a repository registers the user to receive notifications on new discussions, as well as events in the user's activity feed."
+intro: "The Watching API lets users subscribe to notifications for activity in a repository."
 versions:
   fpt: '*'
   ghes: '*'
@@ -11,4 +11,6 @@ topics:
 miniTocMaxHeadingLevel: 3
 ---
 
-For simple repository bookmarks, see "[Repository starring](/rest/reference/activity#starring)."
+## About the Watching API
+
+The Watching API lets users subscribe to notifications for activity in a repository. To bookmark a repository instead, see "[Starring](/rest/reference/activity#starring)."