Apply suggestions from code review

Author: sappelhoff

mne_bids/path.py

@@ -2546,10 +2546,7 @@ def _return_root_paths(root, datatype=None, ignore_json=True, ignore_nosub=False
     else:
         if datatype is not None:
             datatype = _ensure_tuple(datatype)
-            search_str = f"**/{'|'.join(datatype)}/*"
-
-            # I think this one is more appropriate
-            search_str = search_str + ".*"
+            search_str = f"**/{'|'.join(datatype)}/.*"
         else:
             search_str = "**/*.*"