Pass parent exception as context exception to provide clearer stack trace (#21636)

* Pass parent exception as context exception to provide clearer stack trace

* Update src/transformers/tokenization_utils_base.py

Co-authored-by: Sylvain Gugger <35901082+sgugger@users.noreply.github.com>

---------

Co-authored-by: Sylvain Gugger <35901082+sgugger@users.noreply.github.com>

src/transformers/tokenization_utils_base.py

@@ -724,18 +724,18 @@ class BatchEncoding(UserDict):
                     #     tensor = tensor[None, :]
 
                     self[key] = tensor
-            except:  # noqa E722
+            except Exception as e:
                 if key == "overflowing_tokens":
                     raise ValueError(
                         "Unable to create tensor returning overflowing tokens of different lengths. "
                         "Please see if a fast version of this tokenizer is available to have this feature available."
-                    )
+                    ) from e
                 raise ValueError(
                     "Unable to create tensor, you should probably activate truncation and/or padding with"
                     " 'padding=True' 'truncation=True' to have batched tensors with the same length. Perhaps your"
                     f" features (`{key}` in this case) have excessive nesting (inputs type `list` where type `int` is"
                     " expected)."
-                )
+                ) from e
 
         return self