contrib: run editmergeps.ps1 from the same location as editmergeps.bat This change is needed for cases when user does not put editmergeps.bat directly into PATH, but rather uses 'merge-tools.editmergeps.executable' config option to provide a full path to editmergeps.bat. In such cases, editmergeps.ps1 cannot be run simply by name, it needs a full path. In BATCH file %~dp0 stands for the directory in which the original file is located.