added more comments to permissions declared in manifest file

blessed/src/main/AndroidManifest.xml

@@ -2,18 +2,36 @@
     xmlns:tools="http://schemas.android.com/tools"
     package="com.welie.blessed">
 
+    <!-- Link: https://developer.android.com/guide/topics/connectivity/bluetooth/permissions  -->
+    <!-- Request legacy Bluetooth permissions on older devices. -->
     <uses-permission
         android:name="android.permission.BLUETOOTH"
         android:maxSdkVersion="30" />
     <uses-permission
         android:name="android.permission.BLUETOOTH_ADMIN"
         android:maxSdkVersion="30" />
-    <uses-permission android:name="android.permission.BLUETOOTH_CONNECT" />
+
+    <!-- Needed only if code looks for Bluetooth devices.
+         Since the code doesn't use Bluetooth scan results to derive physical
+         location information, it is strongly asserted that the code
+         doesn't derive physical location.
+         Link: https://developer.android.com/guide/topics/connectivity/bluetooth/permissions#assert-never-for-location
+         -->
     <uses-permission
         android:name="android.permission.BLUETOOTH_SCAN"
         android:usesPermissionFlags="neverForLocation"
         tools:targetApi="s" />
+
+    <!-- Needed only if code communicates with already-paired Bluetooth
+         devices. -->
+    <uses-permission android:name="android.permission.BLUETOOTH_CONNECT" />
+
+    <!-- Needed only if code makes the device discoverable to Bluetooth
+         devices. -->
     <uses-permission android:name="android.permission.BLUETOOTH_ADVERTISE" />
+
+    <!-- Needed to target Android 11 and lower   -->
+    <!-- Link: https://developer.android.com/guide/topics/connectivity/bluetooth/permissions#declare-android11-or-lower-->
     <uses-permission
         android:name="android.permission.ACCESS_FINE_LOCATION"
         android:maxSdkVersion="30" />