Reoder pings in the same order as the table of contents

docs/user/pings/index.md

@@ -5,8 +5,8 @@ Every Glean ping is in JSON format and contains one or more of the [common secti
 If data collection is enabled, the Glean SDK provides a set of built-in pings that are assembled out of the box without any developer intervention.  The following is a list of these built-in pings:
 
 - [`baseline` ping](baseline.md)
-- [`events` ping](events.md)
 - [`metrics` ping](metrics.md)
+- [`events` ping](events.md)
 
 Applications can also define and send their own [custom pings](custom.md).
 
@@ -16,11 +16,11 @@ There are two standard metadata sections that are added to most pings, in additi
 
 - The [`ping_info` section](#The-ping_info-section) contains core metadata that is included in **every** ping.
   
-- The [`client_info` section](#The-client_info-section) contains information that identifies the client. 
+- The [`client_info` section](#The-client_info-section) contains information that identifies the client.
   It is included in most pings (including all built-in pings), but may be excluded from pings where we don't want to connect client information with the other metrics in the ping.
 
 ### The `ping_info` section
-The following fields are included in the `ping_info` section, for every ping. 
+The following fields are included in the `ping_info` section, for every ping.
 Optional fields are marked accordingly.
 
 | Field name | Type | Description |
@@ -71,7 +71,7 @@ This object (included in the [`ping_info` section](#The-ping_info-section)) cont
 
 ## Ping submission
 
-The pings that the Glean SDK generates are submitted to the Mozilla servers at specific paths, in order to provide additional metadata without the need to unpack the ping payload. 
+The pings that the Glean SDK generates are submitted to the Mozilla servers at specific paths, in order to provide additional metadata without the need to unpack the ping payload.
 A typical submission URL looks like
 
   `"<server-address>/submit/<application-id>/<doc-type>/<glean-schema-version>/<ping-uuid>"`
@@ -97,8 +97,8 @@ A pre-defined set of headers is additionally sent along with the submitted ping:
 
 ## Defining background state
 
-These docs refer to application 'background' state in several places. 
+These docs refer to application 'background' state in several places.
 This specifically means when the activity is no longer visible to the user, it has entered the Stopped state, and the system invokes the [`onStop()`](https://developer.android.com/reference/android/app/Activity.html#onStop()) callback.
-This may occur, for example, when a newly launched activity covers the entire screen. 
+This may occur, for example, when a newly launched activity covers the entire screen.
 The system may also call `onStop()` when the activity has finished running, and is about to be terminated.