Update editable.tsx

* Run prettier
* Null checks for selection

packages/slate-react/src/components/editable.tsx

@@ -250,20 +250,18 @@ export const Editable = (props: EditableProps) => {
   // The autoFocus TextareaHTMLAttribute doesn't do anything on a div, so it
   // needs to be manually focused.
   useEffect(() => {
-      if (ref.current && autoFocus) {
-        if (window.getSelection && document.createRange) {
-          const range = document.createRange();
-          ref.current.focus();
-          range.setStart(ref.current, ref.current.childNodes.length);
-          range.setEnd(ref.current, ref.current.childNodes.length);
-          const sel = window.getSelection();
-          sel.removeAllRanges();
-          sel.addRange(range);
-        }
-        else
-          ref.current.focus();
-      }
-    }, [autoFocus])
+    if (ref.current && autoFocus) {
+      if (window.getSelection && document.createRange) {
+        const range = document.createRange()
+        ref.current.focus()
+        range.setStart(ref.current, ref.current.childNodes.length)
+        range.setEnd(ref.current, ref.current.childNodes.length)
+        const sel = window.getSelection()
+        sel?.removeAllRanges()
+        sel?.addRange(range)
+      } else ref.current.focus()
+    }
+  }, [autoFocus])
 
   // Listen on the native `selectionchange` event to be able to update any time
   // the selection changes. This is required because React's `onSelect` is leaky