Add RematScope API to keras-io (#2080)

* add RematScope API to keras-io

* add reference

* add keras.remat

* renaming to Rematerialization and remove from  utility section

* version bump

* revert version

Author: laxmareddyp

scripts/api_master.py

@@ -1952,6 +1952,23 @@
                 },
             ],
         },
+        {
+            "path": "rematerialization/",
+            "title": "Rematerialization",
+            "toc": True,
+            "children": [
+                {
+                    "path": "remat_scope",
+                    "title": "RematScope",
+                    "generate": ["keras.RematScope"],
+                },
+                {
+                    "path": "remat",
+                    "title": "Remat",
+                    "generate": ["keras.remat"],
+                },
+            ],
+        },
         {
             "path": "utils/",
             "title": "Utilities",