Brian Steinberg Senior TV EditorBrian Williams, the veteran anchor who became an integral part of MSNBC after a critical on-air gaffe in 2015 while behind the anchor desk at “NBC Nightly News” led to his removal from that landmark program, is parting ways with the cable-news outlet and striking out on his own.His next steps in the news business, or whether he expects to continue in it, remain unknown.“After nearly three decades as an award-winning journalist and anchor at MSNBC and NBC News,