docs: split loader docs (#6442)

* docs: split loader api

* docs: split loader api zh

* docs: remove type decl detail in title

website/docs/en/api/_meta.json

@@ -4,7 +4,11 @@
   "modules",
   "node-api",
   "hmr",
-  "loader-api",
+  {
+    "type": "dir",
+    "name": "loader-api",
+    "label": "Loader API"
+  },
   {
     "type": "dir",
     "name": "plugin-api",

website/docs/en/api/index.mdx

@@ -30,7 +30,7 @@ The Hot Module Replacement (HMR) improves the development experience by updating
 
 Loaders are transformations that are applied to the source code of a module. They are written as functions that accept source code as a parameter and return a new version of that code with transformations applied.
 
-[Learn more about the loaders!](/api/loader-api)
+[Learn more about the loaders!](/api/loader-api/index)
 
 ## Plugins
 

website/docs/en/api/loader-api/_meta.json

@@ -0,0 +1,8 @@
+[
+  "index",
+  "examples",
+  "context",
+  "rspack-specific-properties",
+  "inline",
+  "inline-match-resource"
+]