feat(docs): expand all categories by default

Author: Char2sGu

docs/src/content/cdk/ng-doc.category.ts

@@ -3,6 +3,7 @@ import { NgDocCategory } from '@ng-doc/core';
 const CdkCategory: NgDocCategory = {
   title: 'CDK',
   order: 2,
+  expanded: true,
 };
 
 export default CdkCategory;

docs/src/content/core/ng-doc.category.ts

@@ -3,6 +3,7 @@ import { NgDocCategory } from '@ng-doc/core';
 const CoreCategory: NgDocCategory = {
   title: 'Core',
   order: 1,
+  expanded: true,
 };
 
 export default CoreCategory;