Added hint about notification channel settings

app/src/main/res/layout/fragment_options_notifications.xml

@@ -144,6 +144,18 @@
                 app:layout_constraintStart_toStartOf="parent"
                 app:layout_constraintTop_toBottomOf="@id/tvNotifyActionsPro" />
 
+            <TextView
+                android:id="@+id/tvManageHint"
+                android:layout_width="0dp"
+                android:layout_height="wrap_content"
+                android:layout_marginEnd="48dp"
+                android:text="@string/title_advanced_notify_manage_hint"
+                android:textAppearance="@style/TextAppearance.AppCompat.Small"
+                android:textStyle="italic"
+                app:layout_constraintEnd_toEndOf="parent"
+                app:layout_constraintStart_toStartOf="parent"
+                app:layout_constraintTop_toBottomOf="@id/btnManage" />
+
             <androidx.appcompat.widget.SwitchCompat
                 android:id="@+id/swLight"
                 android:layout_width="match_parent"
@@ -151,7 +163,7 @@
                 android:layout_marginTop="12dp"
                 android:text="@string/title_advanced_light"
                 app:layout_constraintStart_toStartOf="parent"
-                app:layout_constraintTop_toBottomOf="@id/btnManage"
+                app:layout_constraintTop_toBottomOf="@id/tvManageHint"
                 app:switchPadding="12dp" />
 
             <Button

app/src/main/res/values/strings.xml

@@ -222,6 +222,7 @@
     <string name="title_advanced_notify_action_flag">Star</string>
     <string name="title_advanced_notify_action_seen">Read</string>
     <string name="title_advanced_notify_action_hint">At most three actions will be shown</string>
+    <string name="title_advanced_notify_manage_hint">Tap on the channel name \'Notifications\' to set the default notification sound, etc</string>
     <string name="title_advanced_light">Use notification light</string>
     <string name="title_advanced_sound">Select notification sound</string>