Update WordPress pages post type labels.
Supports single instance.
intervention('update-label-page', $labels(string|array));
$labels: null
intervention('update-label-page', 'Contents');
// Updates plural label from Pages to Contents.
intervention('update-label-page', '[Contents, 'Content']');
// Param 1 updates plural label from Pages to Contents.
// Param 2 updates singular label from Page to Content.
intervention('update-label-page', '[Contents, 'Content', 'smiley']');
// Param 1 updates plural label from Pages to Contents.
// Param 2 updates singular label from Page to Content.
// Param 3 updates dashicon to dashicons-smiley.