fix typo (#1285)

mmcv/image/photometric.py

@@ -301,15 +301,15 @@ def adjust_sharpness(img, factor=1., kernel=None):
     image and the degenerated mean image:
 
     .. math::
-    output = img * factor + degenerated * (1 - factor)
+        output = img * factor + degenerated * (1 - factor)
 
     Args:
         img (ndarray): Image to be sharpened. BGR order.
         factor (float): Same as :func:`mmcv.adjust_brightness`.
         kernel (np.ndarray, optional): Filter kernel to be applied on the img
             to obtain the degenerated img. Defaults to None.
 
-    Notes:
+    Notes::
         No value sanity check is enforced on the kernel set by users. So with
         an inappropriate kernel, the `adjust_sharpness` may fail to perform
         the function its name indicates but end up performing whatever