adds .parquet info to ValueError

virtualizarr/readers/kerchunk.py

@@ -63,7 +63,7 @@ def open_virtual_dataset(
 
         else:
             raise ValueError(
-                "The input Kerchunk reference did not seem to be in Kerchunk's JSON or Parquet spec: https://fsspec.github.io/kerchunk/spec.html. The Kerchunk format autodetection is quite flaky, so if your reference matches the Kerchunk spec feel free to open an issue: https://github.com/zarr-developers/VirtualiZarr/issues"
+                "The input Kerchunk reference did not seem to be in Kerchunk's JSON or Parquet spec: https://fsspec.github.io/kerchunk/spec.html. If your Kerchunk generated reference file is in parquet, make sure the file extension is `.parquet`. The Kerchunk format autodetection is quite flaky, so if your reference matches the Kerchunk spec feel free to open an issue: https://github.com/zarr-developers/VirtualiZarr/issues"
             )
 
         # TODO would be more efficient to drop these before converting them into ManifestArrays, i.e. drop them from the kerchunk refs dict