Move notes about SED and SVD commodities to commodities.yaml

Author: alexdewar

schemas/input/commodities.yaml

@@ -1,4 +1,8 @@
 title: Main commodities file
+description: |
+  Every SED (supply equals demand) commodity must have both producer and consumer processes for
+  every region and milestone year. Every SVD (service demand) commodity must have a producer for
+  every region and milestone year.
 
 fields:
   - name: id

schemas/input/processes.yaml

@@ -1,10 +1,4 @@
 title: Main processes file
-description: |
-  Defines processes for the system.
-
-  Every SED (supply equals demand) commodity must have both producer and consumer processes for
-  every region and milestone year. Every SVD (service demand) commodity must have a producer for
-  every region and milestone year.
 
 fields:
   - name: id