feat: jsdocs for generated types, by using admin.description (#9917)

This makes use of admin.description to generate JSDocs for field,
collection and global generated types.


![image](https://github.com/user-attachments/assets/980d825f-49a2-426d-933a-2ff3d205ea24)


![image](https://github.com/user-attachments/assets/d0b1f288-1ea1-4d80-8c05-003d59a4e41a)

For the future, we should add a dedicated property to override these
JSDocs.

You can view the effect of this PR on our test suite generated types
here:
05f552bbbc

test/plugin-nested-docs/payload-types.ts

@@ -88,6 +88,9 @@ export interface Page {
 export interface Category {
   id: string;
   name: string;
+  /**
+   * custom
+   */
   categorization?:
     | {
         doc?: (string | null) | Category;
@@ -97,6 +100,9 @@ export interface Category {
         id?: string | null;
       }[]
     | null;
+  /**
+   * custom
+   */
   owner?: (string | null) | Category;
   updatedAt: string;
   createdAt: string;