Revert "docs: remove outdated FAQ"

This reverts commit 400d313.

README.md

@@ -180,4 +180,32 @@ const ComponentWithErrorBoundary = withErrorBoundary(ExampleComponent, {
 
 ---
 
+# FAQ
+## `ErrorBoundary` cannot be used as a JSX component
+This error can be caused by a version mismatch between [react](https://npmjs.com/package/react) and [@types/react](https://npmjs.com/package/@types/react). To fix this, ensure that both match exactly, e.g.:
+
+If using NPM:
+```json
+{
+  ...
+  "overrides": {
+    "@types/react": "17.0.60"
+  },
+  ...
+}
+```
+
+If using Yarn:
+```json
+{
+  ...
+  "resolutions": {
+    "@types/react": "17.0.60"
+  },
+  ...
+}
+```
+
+---
+
 [This blog post](https://kentcdodds.com/blog/use-react-error-boundary-to-handle-errors-in-react) shows more examples of how this package can be used, although it was written for the [version 3 API](https://github.com/bvaughn/react-error-boundary/releases/tag/v3.1.4).