base/schema: Fix instructions schema

Without the `...` prefix, CUE interprets a type enclosed in square
brackets as a list of exactly one of that type.  The ellipsis changes it
to mean a list of any number of that type.

base/schema/instructions/instructions.cue

@@ -6,7 +6,7 @@ package instructions
 }
 
 #Hooks: {
-	changed?: [#Hook]
+	changed?: [...#Hook]
 }
 
 #RenderInstruction: {
@@ -19,5 +19,5 @@ package instructions
 }
 
 #Instructions: {
-	render: [#RenderInstruction]
+	render: [...#RenderInstruction]
 }