patch 8.2.3936: no proper test for maintaining change mark in diff mode Commit: https://github.com/vim/vim/commit/ccc1644f95e7833c23fa0d440e42293c1622fdcb Author: Sean Dewar <seandewar@users.noreply.github.com> Date: Wed Dec 29 16:44:48 2021 +0000 patch 8.2.3936: no proper test for maintaining change mark in diff mode Problem: No proper test for maintaining change mark in diff mode. Solution: Run the test with internal and external diff. (Sean Dewar, closes #9424)

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