docs: add <Dimmable> reference

docs/en/Dimmable.md

@@ -0,0 +1,31 @@
+# `<Dimmable>`
+
+Dims element similar to [`<Dimmer>`](./Dimmer.md), with additional features:
+
+- Works on server side.
+- Sets `aria-hidden="true"`, if element is dimmed.
+- Sets `pointer-events: none`, if element is dimmed.
+- Blurs dimmed element.
+
+
+## Usage
+
+```jsx
+import {Dimmable} from 'libreact/lib/Dimmable';
+
+<Dimmable dim renderOverlay={(dim) => 'Overlay...'}>
+  <div style={{width: 500, height: 300, border: '1px solid tomato'}}>
+    Inline...
+  </div>
+</Dimmable>
+```
+
+
+## Props
+
+Accepts all [`<Dimmer>` props](./Dimmer.md#props) (except `hidden`, use `dim` instead) in addition to its own:
+
+- `dim` &mdash; optional, boolean, whether to show dim overlay, defaults to `false`.
+- `blur` &mdash; optional, number, blur intensity in `px` when dimmed, defaults to `5`.
+- `renderOverlay` &mdash; optional, function, returns contents to render in overlay when element is dimmed.
+Receives a single argument &mdash; boolean, whether element is dimmed.