Make version mismatch warning actionable

The old warning told users to downgrade, which is unhelpful when they
upgraded intentionally. The new message states both the saved and current
versions and tells the user to re-save the object to update it.

Closes #4495

Author: h-mayorquin

src/spikeinterface/core/base.py

@@ -1144,11 +1144,14 @@ def _load_extractor_from_dict(dic) -> "BaseExtractor":
     extractor_class = _get_class_from_string(class_name)
 
     assert extractor_class is not None and class_name is not None, "Could not load spikeinterface class"
-    is_old_version = not _check_same_version(class_name, dic["version"])
+    module_name = class_name.split(".")[0]
+    current_version = importlib.import_module(module_name).__version__
+    saved_version = dic["version"]
+    is_old_version = not _check_same_version(class_name, saved_version)
     if is_old_version:
         warnings.warn(
-            f"Versions are not the same. This might lead to compatibility errors. "
-            f"Using {class_name.split('.')[0]}=={dic['version']} is recommended"
+            f"This object was saved with {module_name}=={saved_version} and you are running {module_name}=={current_version}. "
+            f"To update the saved version, re-save the object with `save()` or `save_to_folder()`/`save_to_zarr()`."
         )
 
         if hasattr(extractor_class, "_handle_backward_compatibility"):