message: Fix typescript material-ui overrides example
diff: @@ -37,9 +37,13 @@ For TypeScript users it's also required to extend default material-ui theme typi
  (This will also autocomplete classnames)
  ```typescript
  -declare module '@material-ui/core/styles/overrides' {
  - import { MuiPickersOverrides } from '@material-ui/pickers/typings/overrides'
  +import { Overrides } from "@material-ui/core/styles/overrides";
  +import { MuiPickersOverrides } from 'material-ui-pickers/typings/overrides'
  - export interface Overrides extends MuiPickersOverrides { }
  +type overridesNameToClassKey = { [P in keyof MuiPickersOverrides]: keyof
  +MuiPickersOverrides[P] }
  +
  +declare module "@material-ui/core/styles/overrides" {
  + export interface ComponentNameToClassKey extends overridesNameToClassKey { }
  }
  ```
  