Fix toSlatePoint wrong offset for void element. (#4057)

packages/slate-react/src/plugin/react-editor.ts

@@ -483,6 +483,9 @@ export const ReactEditor = {
         textNode = leafNode.closest('[data-slate-node="text"]')!
         domNode = leafNode
         offset = domNode.textContent!.length
+        domNode.querySelectorAll('[data-slate-zero-width]').forEach(el => {
+          offset -= el.textContent!.length
+        })
       }
 
       // COMPAT: If the parent node is a Slate zero-width space, editor is