docs: add RepeatLayer

Author: JackTemaki

docs/layer_reference/shape.rst

@@ -60,21 +60,26 @@ Prefix (in Time) Layer
     :members:
     :undoc-members:
 
-Resize Layer
-------------
+Reinterpret Data Layer
+----------------------
 
-.. autoclass:: returnn.tf.layers.basic.ResizeLayer
+.. autoclass:: returnn.tf.layers.basic.ReinterpretDataLayer
     :members:
     :undoc-members:
 
+Repeat Layer
+------------
 
-Reinterpret Data Layer
-----------------------
-
-.. autoclass:: returnn.tf.layers.basic.ReinterpretDataLayer
+.. autoclass:: returnn.tf.layers.basic.RepeatLayer
     :members:
     :undoc-members:
 
+Resize Layer
+------------
+
+.. autoclass:: returnn.tf.layers.basic.ResizeLayer
+    :members:
+    :undoc-members:
 
 Scatter n-dim Layer
 -------------------