Document new behavior

Author: jlove29

readme.md

@@ -41,6 +41,8 @@ const Demo = () => {
 render(<Demo />);
 ```
 
+The user can select the item with arrow keys (or hjkl) + enter, or by hitting the number of the option directly.
+
 <img src="media/demo.gif" width="508">
 
 ## Props

src/SelectInput.tsx

@@ -137,6 +137,7 @@ function SelectInput<V>({
 					}
 				}
 
+        // Enable selection directly from number keys.
 				if (/^[1-9]$/.test(input)) {
 					const targetIndex = Number.parseInt(input, 10) - 1;