Documenting the effect of the new OrderedDict in ManufacturerData including what it benefits.

Author: Kevin J Walters

adafruit_ble/advertising/standard.py

@@ -212,7 +212,9 @@ def __init__(self, *services):
 class ManufacturerData(AdvertisingDataField):
     """Encapsulates manufacturer specific keyed data bytes. The manufacturer is identified by the
        company_id and the data is structured like an advertisement with a configurable key
-       format."""
+       format. The order of the serialized data is determined by the order that the
+       `ManufacturerDataField` attributes are set in - this can be useful for
+       `match_prefixes` in an `Advertisement` sub-class."""
 
     def __init__(
         self, obj, *, advertising_data_type=0xFF, company_id, key_encoding="B"