Update doc

Author: cecton

website/docs/concepts/function-components/properties.mdx

@@ -263,6 +263,28 @@ fn App() -> Html {
 }
 ```
 
+## Automatically generate properties (autoprops)
+
+In order to streamline your development process, you can also use the macro
+`#[autoprops]` that will automatically generate the `Properties` struct for you.
+
+```rust
+use yew::prelude::*;
+
+#[autoprops]
+#[function_component]
+fn Greetings(
+    #[prop_or("Hello".into())]
+    message: AttrValue,
+    #[prop_or("World".into())]
+    name: AttrValue,
+) -> Html {
+    html! {<>{message}{name}</>}
+}
+
+// The properties struct "GreetingsProps" will be generated automatically.
+```
+
 ## Evaluation Order
 
 Props are evaluated in the order they're specified, as shown by the following example:
@@ -296,7 +318,12 @@ These include, but are not limited to:
    **Why is this bad?** Interior mutability (such as with `RefCell`, `Mutex`, etc.) should
    _generally_ be avoided. It can cause problems with re-renders (Yew doesn't know when the state has changed)
    so you may have to manually force a render. Like all things, it has its place. Use it with caution.
-3. You tell us. Did you run into an edge-case you wish you knew about earlier? Feel free to create an issue
+3. Using `Vec` type instead of `IArray`. <br />
+   **Why is this bad?** `Vec`, just like `String`, can also be expensive to clone. `IArray` is either
+   a reference-counted slice (`Rc<T>`) or a `&'static [T]`, thus very cheap to clone.<br />
+   **Note**: `IArray` can be imported from [implicit-clone](https://crates.io/crates/implicit-clone)
+   See that crate to learn more.
+4. You tell us. Did you run into an edge-case you wish you knew about earlier? Feel free to create an issue
    or PR a fix to this documentation.
 
 ## yew-autoprops