update comments regarding fragment arguments and variables (#4184)

Author: yaacovCR

src/language/ast.ts

@@ -229,11 +229,18 @@ export const QueryDocumentKeys: {
   NonNullAssertion: ['nullabilityAssertion'],
   ErrorBoundary: ['nullabilityAssertion'],
 
-  FragmentSpread: ['name', 'arguments', 'directives'],
+  FragmentSpread: [
+    'name',
+    // Note: Fragment arguments are experimental and may be changed or removed
+    // in the future.
+    'arguments',
+    'directives',
+  ],
   InlineFragment: ['typeCondition', 'directives', 'selectionSet'],
   FragmentDefinition: [
     'name',
-    // Note: fragment variable definitions are deprecated and will removed in v17.0.0
+    // Note: Fragment variables are experimental and may be changed or removed
+    // in the future.
     'variableDefinitions',
     'typeCondition',
     'directives',