improve the document of storage (#3731)

Add “Needs `storage_secret`” to table. Improve description of `app.storage.user` and `app.storage.browser`.

website/documentation/content/storage_documentation.py

@@ -32,17 +32,19 @@
         Stored server-side, each dictionary is associated with a unique identifier held in a browser session cookie.
         Unique to each user, this storage is accessible across all their browser tabs.
         `app.storage.browser['id']` is used to identify the user.
+        This storage is only available within [page builder functions](/documentation/page) 
+        and requires the `storage_secret` parameter in`ui.run()` to sign the browser session cookie.
     - `app.storage.general`:
         Also stored server-side, this dictionary provides a shared storage space accessible to all users.
     - `app.storage.browser`:
         Unlike the previous types, this dictionary is stored directly as the browser session cookie, shared among all browser tabs for the same user.
         However, `app.storage.user` is generally preferred due to its advantages in reducing data payload, enhancing security, and offering larger storage capacity.
         By default, NiceGUI holds a unique identifier for the browser session in `app.storage.browser['id']`.
+        This storage is only available within [page builder functions](/documentation/page) 
+        and requires the `storage_secret` parameter in`ui.run()` to sign the browser session cookie.
 
-    The user storage and browser storage are only available within `page builder functions </documentation/page>`_
-    because they are accessing the underlying `Request` object from FastAPI.
-    Additionally these two types require the `storage_secret` parameter in`ui.run()` to sign the browser session cookie.
-
+    The following table will help you to choose storage.
+ 
     | Storage type                | `tab`  | `client` | `user` | `general` | `browser` |
     |-----------------------------|--------|----------|--------|-----------|-----------|
     | Location                    | Server | Server   | Server | Server    | Browser   |
@@ -54,6 +56,7 @@
     | Needs client connection     | Yes    | No       | No     | No        | No        |
     | Write only before response  | No     | No       | No     | No        | Yes       |
     | Needs serializable data     | No     | No       | Yes    | Yes       | Yes       |
+    | Needs `storage_secret`      | No     | No       | Yes    | No        | Yes       |
 ''')
 def storage_demo():
     from nicegui import app