batches: clarify on.repository error message when for incorrect repo path

Created by: adeola-ak

Closes https://github.com/sourcegraph/src-cli/pull/733 https://github.com/sourcegraph/sourcegraph/issues/33778

I was going back and fourth between this error message:

no repository found: double-check your spelling and make sure to specify the repository in the format "<codehost_url>/owner/repo-name" & no repository found: did you check spelling and specify the repository in the format "<codehost_url>/owner/repo-name"?

Thoughts?

Also, I believe the SSBC error for this operation may also not be clear enough and could benefit from being changed to whatever we decide above. It reads: Resolving "r:sourcegraph": repo not found: name="sourcegraph"

note: duplicate of this closed issue after i realizing i was working in forked version

Test plan

observed visual change in error text in src cli