doc updates

Author: kbond

src/Icons/README.md

@@ -52,6 +52,17 @@ directory using the `ux:icons:import` command:
  bin/console ux:icons:import flowbite:user-solid flowbite:home-solid
  ```
 
+> [!NOTE]
+> Imported icons must be committed to your repository.
+
+#### On-Demand VS Import
+
+While _on-demand_ icons are great during development, they require http requests to fetch the icon
+and always use the _latest version_ of the icon. It's possible the icon could change or be removed
+in the future. Additionally, the cache warming process will take significantly longer if using
+many _on-demand_ icons. You can think of importing the icon as _locking it_ (similar to how
+`composer.lock` _locks_ your dependencies).
+
 ## Usage
 
 ```twig
@@ -91,6 +102,9 @@ This command looks in all your twig templates for `ux_icon` calls and caches the
 > During development, if you modify an icon, you will need to clear the cache (`bin/console cache:clear`)
 > to see the changes.
 
+> [!TIP]
+> If using `symfony/asset-mapper`, the cache is warmed automatically when running `asset-map:compile`.
+
 ## Full Default Configuration
 
 ```yaml
@@ -103,7 +117,7 @@ ux_icons:
         # Default:
         fill: currentColor
 
-    # Configuration for the Iconify.design functionality.
+    # Configuration for the "on demand" icons powered by Iconify.design.
     iconify:
        enabled:              true