Add information about optional sizes to docs

src/bootstrap/Modal.md

@@ -1,8 +1,19 @@
 Bootstrap modal component.
 
-it's required to have an element `<div id={"modal-container"}/>` somewhere on
+It's required to have an element `<div id={"modal-container"}/>` somewhere on
 the page since modals are rendered in portals.
 
+Modals also have three optional sizes, which can be defined through the `size`
+prop:
+
+-   small - `sm`
+-   large - `lg`
+-   extra-large - `xl`
+
+For more details please visit Bootstrap
+<a href="https://getbootstrap.com/docs/4.5/components/modal/#optional-sizes" target="_blank">
+documentation</a>.
+
 ```js
 <div id="modal-container" />
 ```
@@ -14,7 +25,7 @@ import { useState } from "react";
 const [shown, setShown] = useState(false);
 
 <>
-    <Modal setShown={setShown} shown={shown}>
+    <Modal setShown={setShown} shown={shown} size="sm">
         <ModalHeader setShown={setShown} title="Warning!" />
         <ModalBody>
             <p>Bla bla bla...</p>