$T AT&T  (T) - Get AT&T Inc. Report shares jumped higher Thursday after analysts at Morgan Stanley boosted their rating on the stock as it moves closer to sealing its planned $43 billion media merger with Discovery.  Morgan Stanley analyst Simon Flannery raised his rating on AT&T to 'overweight' from 'equal-weight', arguing that the recent move to combine its media assets with Discovery  (DISCA) - Get Discovery, Inc. Class A Report will leave the Dallas-based group "a much clearer and focused communications business". However, he also lowered his price target on the group by $4, to $28 a share.