split: handle partial commit of copies when doing split or record When using split or record, using either interface (text or curses), selecting portions of the file to be committed/recorded did not work; the entire file was treated as having been selected. This appears to be because the logic for handling partial application of the patches relies on knowing what files are "new with modifications", and it doesn't treat "copy destination" as "new". Handling renames correctly is more difficult and will be done in a later patch. Differential Revision: https://phab.mercurial-scm.org/D6767