chore(contented-example): Linking guideline (#544)

#### What this PR does / why we need it:

As per title, add notes on Linking.

packages/contented-example/docs/04-markdown.md

@@ -48,6 +48,76 @@ title: Markdown Flavour
 ---
 ```
 
+## Linking
+
+```md
+[Heading](#linking)
+[External](https://example.com)
+[Relative Example 1](relative)
+[Relative Example 2](to/folder/page-1)
+[Relative Example 3](../back/page-3)
+```
+
+It is highly recommended to use relative links for internal linking and avoid using absolute links.
+This is because contented pipelines are designed to be portable and can be deployed to different sites or domains.
+By using absolute links, you're assuming that the content will always be deployed to the same domain or the same path.
+When using relative links, contented will automatically resolve the links to the correct destination.
+
+For example:
+
+```js
+/** @type {import('@contentedjs/contented').ContentedConfig} */
+const config = {
+  preview: {
+    url: 'https://preview.contented.dev',
+    name: 'Preview Contented',
+  },
+  processor: {
+    rootDir: '../docs',
+    pipelines: [
+      {
+        type: 'ExampleType',
+        pattern: 'example-docs/**/*md',
+        processor: 'md',
+        transform: (file) => {
+          // Notice that the path example-docs/ is removed. There is no way to know how you path is structured.
+          // You need therefore use relative links that works universally across all sites.
+          // This is intentional to make contented pipelines portable.
+          file.path = file.path.replaceAll(/^\/example-docs\/?/g, '/');
+          file.sections = file.sections.slice(1);
+          return file;
+        },
+      },
+    ],
+  },
+};
+
+export default config;
+```
+
+```txt
+Pipeline Processed:                 -> /[path] (note docs/example-docs/ is removed)
+/docs/example-docs/page-1           -> /page-1
+/docs/example-docs/page-2           -> /page-2
+/docs/example-docs/folder/page-3    -> /folder/page-3
+
+Preview:                            -> https://preview.contented.dev/[type]/[path]
+/page-1                             -> https://preview.contented.dev/example/page-1
+/page-2                             -> https://preview.contented.dev/example/page-2
+/folder/page-3                      -> https://preview.contented.dev/example/folder/page-3
+
+Another Site:                       -> https://developer-docs.com/product-example/docs/[path]
+/page-1                             -> https://developer-docs.com/product-example/docs/page-1
+/page-2                             -> https://developer-docs.com/product-example/docs/page-2
+/folder/page-3                      -> https://developer-docs.com/product-example/docs/folder/page-3
+```
+
+Note how "Another Site" consumed the same contented pipeline but deployed to a different domain and path with its own
+custom prefix. If you used absolute links, the links would be broken.
+
+It is also highly advised against linking to another `"Type"` as you're assuming that the other site will be
+structured the same way as your site with the same prefix or even publishing that `"Type"` at all.
+
 ## Admonitions
 
 Admonitions with `remark-directive` and `remark-directive-rehype`.
@@ -122,8 +192,8 @@ graph LR
 
 ```mermaid
   graph TD;
-      A-->B;
-      A-->C;
-      B-->D;
-      C-->D;
+A --> B;
+A --> C;
+B --> D;
+C --> D;
 ```