Fix anchor link, add some scroll margin to h4 headings (#7810)

Author: hbuchel

src/pages/gen1/[platform]/build-a-backend/graphqlapi/data-modeling/index.mdx

@@ -907,7 +907,7 @@ type Query {
 
 The example above creates a custom query that utilizes the `@function` directive to call a Lambda function for this query.
 
-For the type definitions of queries, mutations, and subscriptions, see [Type Definitions of the `@model` Directive](#type-definition-of-the-`@model`-directive).
+For the type definitions of queries, mutations, and subscriptions, see [Type Definitions of the `@model` Directive](#type-definition-of-the-model-directive).
 
 ### Customize creation and update timestamps
 
@@ -1151,7 +1151,7 @@ The `@model` directive will generate:
 - Filter input objects that allow you to filter objects in list queries and relationship fields.
 - For list queries the default number of objects returned is 100. You can override this behavior by setting the limit argument.
 
-**Type definition of the `@model` directive**
+#### Type definition of the `@model` directive
 
 ```graphql
 directive @model(

src/styles/base.scss

@@ -116,7 +116,8 @@ kbd {
 
 .main {
   & > h2,
-  & > h3 {
+  & > h3,
+  & > h4 {
     scroll-margin-block: 9rem;
   }
 }