Partial hunk staging doesn't work with nvim as EDITOR environment variable

[nikita-talalai]

Step to reproduce:

1. Set EDITOR=nvim
2. In nvim run :G to open git status
3. Press "P" mapping on unstaged file
4. Choose to edit hunk
5. Make changes and save
   It doesn't return to previous buffer after saving and quitting (to continue processing other hunks). It returns to git status split with unapplied changes.
   However, editing hunk with, for example, nano, is working as expected.