touched up exception handling

Author: tclose

fileformats/core/datatype.py

@@ -125,7 +125,7 @@ def from_mime(cls, mime_string):
         except ValueError:
             raise FormatRecognitionError(
                 f"Format '{mime_string}' is not a valid MIME-like format of <namespace>/<format>"
-            )
+            ) from None
         else:
             namespace = namespace.replace("-", "_")
         # Attempt to load file type using their `iana_mime` attribute