Amending merge commit results in merge conflicts

[OliverJAsh]

Describe the bug Amending merge commit results in merge conflicts.

To Reproduce Try to amend a merge commit by making changes then selecting merge commit in the commits panel and using the keyboard shortcut A

Expected behavior The amend is successful without merge conflicts, seeing as the merge conflicts were already handled when the original merge commit was made.

Screenshots Example using this repo where the latest commit is a merge commit: https://github.com/OliverJAsh/lazygit-amend-merge-test

https://user-images.githubusercontent.com/921609/189199590-264cc0d7-2dd9-4bff-bfa8-63dd6db83103.mov

Version info:

$ lazygit --version
commit=, build date=, build source=homebrew, version=0.35, os=darwin, arch=arm64

$ git --version
git version 2.37.3