Disambiguate error message when running from non-git repo

[NeemaB]

trafficstars

Add the assertGitRepo() check earlier in the commit pipeline to display:

—  ✖ Error: Command failed with exit code 128: git rev-parse
fatal: not a git repository (or any of the parent directories): .git

instead of:

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—  No changes detected

feat(commit.ts): add error handling for assertGitRepo in top level commit to improve user feedback. fix(commit.ts: move assertGitRepo call into try/catch block to handle appropriately