docs: fix broken link in FragmentActivity am: a6ad2d89f4 am: 4428d366b2  -s ours am: 1f9143366a am: dc6ca92f27 am: 3f7f645654
am: dd50e1d85a

Change-Id: I19a927589fc85c4ef122c8c61eb05e1261823dca