Indicate that photo reordering will update the product cover

Author: JorgeMucientes

WooCommerce/src/main/res/layout/fragment_product_images.xml

@@ -60,7 +60,7 @@
                 android:layout_width="match_parent"
                 android:layout_height="wrap_content"
                 android:gravity="center"
-                android:text="@string/product_images_drag_and_drop_description" />
+                android:text="@string/product_images_drag_and_drop_to_reorder" />
 
             <com.google.android.material.textview.MaterialTextView
                 android:id="@+id/textWarning"

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

@@ -2417,7 +2417,7 @@
     <string name="media_picker_dialog_title">Select Media Source</string>
     <string name="wpmedia_picker_title">WordPress media library</string>
     <string name="product_images_image_limit_warning">Only one photo can be displayed per product variation</string>
-    <string name="product_images_drag_and_drop_description">Drag and drop to re-order photos</string>
+    <string name="product_images_drag_and_drop_to_reorder">Drag and drop to re-order photos. The first photo will be set as the cover.</string>
     <string name="product_images_validate_drag_and_drop">Validate</string>
     <string name="product_image_service_error_media_null">Media could not be found</string>
     <string name="product_image_service_error_uploading_single">%d file couldn\'t be uploaded</string>