fix forced update in TextString in case of double render (#4556)

* fix forced update in TextString in case of double render

* added changeset

.changeset/smart-eyes-enjoy.md

@@ -0,0 +1,5 @@
+---
+'slate-react': patch
+---
+
+fix forced update in TextString in case of double render

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

@@ -59,17 +59,17 @@ const TextString = (props: { text: string; isTrailing?: boolean }) => {
   const { text, isTrailing = false } = props
 
   const ref = useRef<HTMLSpanElement>(null)
-  const forceUpdateFlag = useRef(false)
+  const forceUpdateCount = useRef(0)
 
   if (ref.current && ref.current.textContent !== text) {
-    forceUpdateFlag.current = !forceUpdateFlag.current
+    forceUpdateCount.current += 1
   }
 
   // This component may have skipped rendering due to native operations being
   // applied. If an undo is performed React will see the old and new shadow DOM
   // match and not apply an update. Forces each render to actually reconcile.
   return (
-    <span data-slate-string ref={ref} key={forceUpdateFlag.current ? 'A' : 'B'}>
+    <span data-slate-string ref={ref} key={forceUpdateCount.current}>
       {text}
       {isTrailing ? '\n' : null}
     </span>