Make capitalizing work for iOS (#5654)

* Make capitalizing work for iOS

* Add changeset

---------

Co-authored-by: Alexey Starostin <astarostin@astarostin-pc.local>

Author: alex-starostin

.changeset/stale-bats-jog.md

@@ -0,0 +1,5 @@
+---
+'slate-react': minor
+---
+
+Make capitalizing work for iOS

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

@@ -3,7 +3,7 @@ import { Editor, Text, Path, Element, Node } from 'slate'
 
 import { ReactEditor, useSlateStatic } from '..'
 import { useIsomorphicLayoutEffect } from '../hooks/use-isomorphic-layout-effect'
-import { IS_ANDROID } from '../utils/environment'
+import { IS_ANDROID, IS_IOS } from '../utils/environment'
 import { MARK_PLACEHOLDER_SYMBOL } from '../utils/weak-maps'
 
 /**
@@ -129,7 +129,7 @@ export const ZeroWidthString = (props: {
 
   return (
     <span {...attributes}>
-      {!IS_ANDROID || !isLineBreak ? '\uFEFF' : null}
+      {!(IS_ANDROID || IS_IOS) || !isLineBreak ? '\uFEFF' : null}
       {isLineBreak ? <br /> : null}
     </span>
   )