Update docs (#1001)

* docs(tree-view): avoid redundant copy

* docs(search): "clear" is dispatched when pressing "Escape"

* docs(search): refactor "Expandable variant" to demonstrate reactivity

docs/src/pages/framed/Search/SearchExpandableReactive.svelte

@@ -0,0 +1,12 @@
+<script>
+  import { Search } from "carbon-components-svelte";
+
+  let expanded = false;
+</script>
+
+<Search expandable bind:expanded on:expand on:collapse />
+
+<br />
+
+<strong>Expanded:</strong>
+{expanded}