Camera: Document face detection confidence recommendations.

        public Rect rect;

        /**

         * The confidence level for the detection of the face. The range is 1 to 100. 100 is the

         * highest confidence.

         * <p>The confidence level for the detection of the face. The range is 1 to

         * 100. 100 is the highest confidence.</p>

         *

         * <p>Depending on the device, even very low-confidence faces may be

         * listed, so applications should filter out faces with low confidence,

         * depending on the use case. For a typical point-and-shoot camera

         * application that wishes to display rectangles around detected faces,

         * filtering out faces with confidence less than 50 is recommended.</p>

         *

         * @see #startFaceDetection()

         */