update ValueError message for wild card matching for remote files (#5851)

* update ValueError message for wild card matching

* f string

Author: raybellwaves

xarray/backends/api.py

@@ -859,10 +859,9 @@ def open_mfdataset(
             paths = [fs.get_mapper(path) for path in paths]
         elif is_remote_uri(paths):
             raise ValueError(
-                "cannot do wild-card matching for paths that are remote URLs: "
-                "{!r}. Instead, supply paths as an explicit list of strings.".format(
-                    paths
-                )
+                "cannot do wild-card matching for paths that are remote URLs "
+                f"unless engine='zarr' is specified. Got paths: {paths}. "
+                "Instead, supply paths as an explicit list of strings."
             )
         else:
             paths = sorted(glob(_normalize_path(paths)))