fix: add missing word to error message

[karawoo]

Description

An error message says "Could create runtime directory" when I believe it should say "Could not create runtime directory".

Checklist

I have (if applicable):

• filed a contributor agreement.
• referenced the GitHub issue this PR closes
• updated the appropriate changelog in the PR
• ensured the present test suite passes
• added new tests
• created a separate documentation PR in Quarto's website repo and linked it to this PR

[posit-snyk-bot]

✅ Snyk checks have passed. No issues have been found so far.

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✅	Licenses	0	0	0	0	0 issues

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[cscheid]

Thank you!