ElasticTransform docs: fix issue#8879 (#9350)

Co-authored-by: ribbon-otter <ribbon-otter@github.invalid>
Co-authored-by: zy1git <zycoding1@gmail.com>

Author: 3 people

torchvision/transforms/v2/_geometry.py

@@ -1030,8 +1030,10 @@ class ElasticTransform(Transform):
         see-through-water-like effect.
 
     Args:
-        alpha (float or sequence of floats, optional): Magnitude of displacements. Default is 50.0.
-        sigma (float or sequence of floats, optional): Smoothness of displacements. Default is 5.0.
+        alpha (float or sequence of floats, optional): Magnitude of displacements.
+            Default is 50.0. A single value is ``[alpha, alpha]``.
+        sigma (float or sequence of floats, optional): Smoothness of displacements.
+            Default is 5.0. A single value is ``[sigma, sigma]``.
         interpolation (InterpolationMode, optional): Desired interpolation enum defined by
             :class:`torchvision.transforms.InterpolationMode`. Default is ``InterpolationMode.BILINEAR``.
             If input is Tensor, only ``InterpolationMode.NEAREST``, ``InterpolationMode.BILINEAR`` are supported.