Guard MergeNB against merge.tool=nbdime and provide terminal-ready remediation#85

Copilot wants to merge 3 commits intomainAvni2000/MergeNB:mainfrom

copilot/add-nbdime-check-to-git-integrationAvni2000/MergeNB:copilot/add-nbdime-check-to-git-integrationCopy head branch name to clipboard