message: core: fix warnings introduced in React v16.13.0
diff: @@ -167,11 +167,13 @@ export function SubDocumentEditor({ id, pluginProps }: SubDocumentProps) {
  const renderIntoSettings = React.useCallback(
  (children: React.ReactNode) => {
  - setHasSettings(true)
  - if (!settingsRef.current) return null
  - return createPortal(
  - <IgnoreKeys>{children}</IgnoreKeys>,
  - settingsRef.current
  + return (
  + <RenderIntoSettings
  + setHasSettings={setHasSettings}
  + settingsRef={settingsRef}
  + >
  + {children}
  + </RenderIntoSettings>
  )
  },
  [settingsRef]
  @@ -266,3 +268,19 @@ export function SubDocumentEditor({ id, pluginProps }: SubDocumentProps) {
  store
  ])
  }
  +
  +function RenderIntoSettings({
  + children,
  + setHasSettings,
  + settingsRef
  +}: {
  + children: React.ReactNode
  + setHasSettings: (value: boolean) => void
  + settingsRef: React.MutableRefObject<HTMLDivElement>
  +}) {
  + React.useEffect(() => {
  + setHasSettings(true)
  + })
  + if (!settingsRef.current) return null
  + return createPortal(<IgnoreKeys>{children}</IgnoreKeys>, settingsRef.current)
  +}
  