docs: Added desc. of launcher app criteria in Q

As of Android Q, an app is included in the return value of
LauncherApps#getActivityList() unless it fulfills specific criteria.
This CL describes the conditions necessary for an app's activities
to *not* appear in the list.

Test: make ds-docs -j32

Bug: 130352392
Change-Id: Iad888a7a7f47d090da1b143ac152705577144d20

core/java/android/content/pm/LauncherApps.java

@@ -507,6 +507,18 @@ public class LauncherApps {
      * {@link Intent#CATEGORY_LAUNCHER}, for a specified user. Result may include
      * synthesized activities like app details Activity injected by system.
      *
+     * <p>As of <a href="/reference/android/os/Build.VERSION_CODES.html#Q">Android Q</a>, the
+     * launchable activities for a given app are included in the returned list unless the app
+     * satisfies at least one of the following conditions:</p>
+     * <ul>
+     * <li>The app is a system app.</li>
+     * <li>The app doesn't declare any <a href="/guide/topics/permissions/overview">permissions</a>.
+     * </li>
+     * <li>The <code>&lt;application&gt;</code> tag in the app's manifest file doesn't contain any
+     * child elements that represent
+     * <a href="/guide/components/fundamentals#DeclaringComponents">app components</a>.</li>
+     * </ul>
+     *
      * @param packageName The specific package to query. If null, it checks all installed packages
      *            in the profile.
      * @param user The UserHandle of the profile.