Added annotation typing to models._utils (#2854)

* style: Added typing in models._utils

* fix: Removed non-necessary import

* fix: Removed type annotation of forward method

* refactor: Removed un-necessary import

Author: frgfm

torchvision/models/_utils.py

@@ -2,7 +2,7 @@
 
 import torch
 from torch import nn
-from torch.jit.annotations import Dict
+from typing import Dict
 
 
 class IntermediateLayerGetter(nn.ModuleDict):
@@ -41,7 +41,7 @@ class IntermediateLayerGetter(nn.ModuleDict):
         "return_layers": Dict[str, str],
     }
 
-    def __init__(self, model, return_layers):
+    def __init__(self, model: nn.Module, return_layers: Dict[str, str]):
         if not set(return_layers).issubset([name for name, _ in model.named_children()]):
             raise ValueError("return_layers are not present in model")
         orig_return_layers = return_layers