Add option specifically to resolve modified-deleted merge conflicts

[Protonull]

If you are rebasing or merging BranchB onto BranchA, but BranchA has modified a file and BranchB has deleted that file (or vice versa), there doesn't seem to be a clear and idiot-proof way to resolve this. You can stash, discard, or reset the file, but it's not entirely clear what these would do. And attempting to ENTER the file, as you would with any other conflicted change, gets you a Can only stage individual lines for tracked files error. Perhaps ENTER could, in these kinds of scenarios, instead present a dialogue that lets you choose between the versions of the file similarly to Gitkraken: