Update missing copyrights
Copyright line is now " Copyright (C) 2013 - 2019 Merlin contributors".
IANAL, I have no idea what I am doing.
@avsm: Flow copyright is copied there (with the path to MIT LICENSE updated) https://github.com/ocaml/merlin/pull/908/files#diff-1ead05ed940a205c93fcfead82ab8caeR36
(IANAL also) My understanding of the Merlin repository is that the original MIT license was added to the repository 6 years ago. Since then, the common understanding is that any contributions sent here via PRs would be covered by that license as well. Therefore, you can define the Merlin contributors somewhere in the repository as the assemblage of those GitHub ids. So the PR here seems fine to me, with some clarification perhaps being helpful about who those contributors are so there is no ambiguity.
Should be this one reconsidered too? Would be a nice addition for the next release (with 4.09 support) if accepted