Remove quantity from OptogeneticStimulusSite and ImagingPlane definitions (#472)

Author: rly

core/nwb.ogen.yaml

@@ -24,7 +24,6 @@ groups:
 - neurodata_type_def: OptogeneticStimulusSite
   neurodata_type_inc: NWBContainer
   doc: A site of optogenetic stimulation.
-  quantity: '*'
   datasets:
   - name: description
     dtype: text

core/nwb.ophys.yaml

@@ -169,7 +169,6 @@ groups:
 - neurodata_type_def: ImagingPlane
   neurodata_type_inc: NWBContainer
   doc: An imaging plane and its metadata.
-  quantity: '*'
   datasets:
   - name: description
     dtype: text

docs/format/source/format_release_notes.rst

@@ -1,10 +1,12 @@
 Release Notes
 =============
 
-2.4.0 (Upcoming)
+2.4.0 (Aug. 7, 2021)
 ----------------
 
 - Fix incorrect dtype for electrodes table column "filtering" (float -> text)
+- Remove "quantity: *" from the type definitions of ``OptogeneticStimulusSite`` and ``ImagingPlane``.
+  This change improves clarity of the schema to follow best practices. It has no functional effect on the schema.
 
 2.3.0 (May 12, 2021)
 ---------------------