Disable pagination in posts and pages

function wpse_disable_pagination( $query ) {
  if( $query->is_single() && $query->is_page() ) {
    $query->set( 'nopaging' , true );
  }
}
add_action( 'pre_get_posts', 'wpse_disable_pagination' );

NOTE: nopaging (boolean) – show all posts or use pagination. Default value is ‘false’, use paging.