docs: update editable

Author: segunadebayo

website/data/snippets/svelte/editable/custom-controls.mdx

@@ -11,7 +11,7 @@
 <div {...api.getRootProps()}>
   <div {...api.getAreaProps()}>
     <input {...api.getInputProps()} />
-    <span {...api.getPreviewProps()}></span>
+    <span {...api.getPreviewProps()}>{api.valueText}</span>
   </div>
   <div>
     {#if !api.editing}

website/data/snippets/svelte/editable/usage.mdx

@@ -11,7 +11,7 @@
 <div {...api.getRootProps()}>
   <div {...api.getAreaProps()}>
     <input {...api.getInputProps()} />
-    <span {...api.getPreviewProps()}></span>
+    <span {...api.getPreviewProps()}>{api.valueText}</span>
   </div>
 </div>
 ```