fix(load): fix type for NON_OPERATION_KINDS (#4051)

* fix(load): fix type for NON_OPERATION_KINDS

* Add changeset

Author: rosston

.changeset/famous-owls-sit.md

@@ -0,0 +1,5 @@
+---
+'@graphql-tools/load': patch
+---
+
+Fix type error on NON_OPERATION_KINDS when using with graphql@15

packages/load/src/documents.ts

@@ -12,7 +12,7 @@ export const OPERATION_KINDS: KindList = [Kind.OPERATION_DEFINITION, Kind.FRAGME
 /**
  * Kinds of AST nodes that are included in type system definition documents
  */
-export const NON_OPERATION_KINDS = Object.keys(Kind)
+export const NON_OPERATION_KINDS: KindList = Object.keys(Kind)
   .reduce((prev, v) => [...prev, Kind[v]], [] as KindList)
   .filter(v => !OPERATION_KINDS.includes(v));