am 287987db: add style for \'new-child\' class, which hides the "new" tag when the parent list item is expanded (for use when the parent is advertising a new child doc)

* commit '287987db4f47a770f9e48375c02fdb3369190f14':
  add style for 'new-child' class, which hides the "new" tag when the parent list item is expanded (for use when the parent is advertising a new child doc)