Update CONTRIBUTING.md

CONTRIBUTING.md

@@ -18,9 +18,8 @@ When writing new definitions, there are some important guidelines to follow:
 - Every unique model number requires a discrete definition file, even if the set of components is identical.
 - Definition files must end in `.yaml`, or `.yml`
 - Use proper, human-friendly names when creating manufacturer directories (e.g. `Alcatel-Lucent` versus `alcatel`).
-- Include only components which are fixed to the chassis. Optional modular components should be omitted from the
-  definition. (Note that this does not exclude field-replaceable hardware that is expected to always be present, such
-  as power supplies.)
+- Include only components which are fixed to the chassis. Module bays and associated module types should be included for
+  all modular components which can be modelled in NetBox (network modules, power supplies, etc).
 - Name components exactly as they appear in the device's operating system (as opposed to the physical chassis label, if
   different).
 - Use the complete form of interface names where applicable. For example, use `TenGigabitEthernet1/2/3` instead of