amend: prevent '\n' in the note string This comes from the evolve function. I'm not sure why this check was missing in core, since it was present when the length check was added to evolve. I didn't flag this as BC because 530b7361e3a9 mentioned this argument wasn't added to the release notes due to no display capability, and that hasn't changed AFAIK. Differential Revision: https://phab.mercurial-scm.org/D6854