docs: improve telemetry doc (#2534)

Improvements to the update services section plus other minor overall improvements

docs/telemetry.md

@@ -28,17 +28,25 @@ workbench.commandPalette.experimental.enableNaturalLanguageSearch
 ```
 It is also recommended that you review all the settings that "use online services" by following [these instructions](https://code.visualstudio.com/docs/getstarted/telemetry#_managing-online-services). You can use the search filter `@tag:usesOnlineServices` to show such settings and review what to change.
 
-*Note: on Linux, the app update service (extensions are not affected) is disabled completely even if the `update.mode` preference is configured.*
-
-__Please note that some extensions send telemetry data to Microsoft as well. We have no control over this and can only recommend removing the extension.__ _(For example, the C# extension `ms-vscode.csharp` sends tracking data to Microsoft.)_ Be sure to check each extension's settings page to disable its telemetry if applicable.
+__Please note that some extensions send telemetry data to Microsoft as well. We have no control over this and can only recommend removing the extension.__  
+For example, the C# extension `ms-vscode.csharp` sends tracking data to Microsoft. Be sure to check each extension's settings page to disable their telemetry if applicable.
 
 ### Update services
-The app periodically fetches connections to check for the latest version and download it to install.
+By default, the app periodically fetches connections to check for the latest version available to download and install.  
+Extensions are also checked for updates automatically from time to time.
+
+If you want to prevent such behaviors, modify the following preferences:
 
-If you want to prevent such behavior, modify the following preferences:
+For the app itself:
 - `update.mode` -> `manual` (or `none`)
 - `update.enableWindowsBackgroundUpdates` -> `false` (only applicable for Microsoft Windows)
 
+For extensions:
+- `extensions.autoUpdate` -> `false`
+- `extensions.autoCheckUpdates` -> `false`
+
+*Note: on Linux, the app update service is disabled completely at build-time even if the `update.mode` preference is configured. This is because users will more likely use their package managers to update the app rather than updating via the app itself.*
+
 ### Feedback telemetry
 By default, we keep the preference `telemetry.feedback.enabled` enabled. It's used to allow the button `Report Issue...` to be used on the app depending on the context. It does not send any data by having it enabled (other options already cover it). If you want, you can disable this behavior by toggling the preference value.