directory_path for FSx FileSystemInput

Added details on what should be directory_path in FileSystemInput for FSxLustre file_system_type, as it is not an arbitrary path

Author: anatoly-khomenko

src/sagemaker/inputs.py

@@ -263,6 +263,11 @@ def __init__(
                 the file system.
                 Reference: https://docs.aws.amazon.com/efs/latest/ug/mounting-fs.html and
                 https://docs.aws.amazon.com/fsx/latest/LustreGuide/mount-fs-auto-mount-onreboot.html
+                Note:
+                For the FSxLustre the directory_path = f"/{MountName}/{FileSystemPath}"
+                from these cli commands: 
+                aws fsx describe-file-systems --file-system-ids <FSx filesystem ID>
+                aws fsx describe-data-repository-associations --association-ids <Data Repository Association ID>
             file_system_access_mode (str): Permissions for read and write.
                 Valid values: 'ro' or 'rw'. Defaults to 'ro'.
         """