Flax Regnet (#21867)

* initial commit

* review changes

* post model PR merge

* updating doc

docs/source/en/index.mdx

@@ -377,7 +377,7 @@ Flax), PyTorch, and/or TensorFlow.
 |              RAG              |       ✅       |       ❌       |       ✅        |         ✅         |      ❌      |
 |             REALM             |       ✅       |       ✅       |       ✅        |         ❌         |      ❌      |
 |           Reformer            |       ✅       |       ✅       |       ✅        |         ❌         |      ❌      |
-|            RegNet             |       ❌       |       ❌       |       ✅        |         ✅         |      ❌      |
+|            RegNet             |       ❌       |       ❌       |       ✅        |         ✅         |      ✅      |
 |            RemBERT            |       ✅       |       ✅       |       ✅        |         ✅         |      ❌      |
 |            ResNet             |       ❌       |       ❌       |       ✅        |         ✅         |      ✅      |
 |           RetriBERT           |       ✅       |       ✅       |       ✅        |         ❌         |      ❌      |

docs/source/en/model_doc/regnet.mdx

@@ -67,4 +67,16 @@ If you're interested in submitting a resource to be included here, please feel f
 ## TFRegNetForImageClassification
 
 [[autodoc]] TFRegNetForImageClassification
-    - call
+    - call
+
+
+## FlaxRegNetModel
+
+[[autodoc]] FlaxRegNetModel
+    - __call__
+
+
+## FlaxRegNetForImageClassification
+
+[[autodoc]] FlaxRegNetForImageClassification
+    - __call__