quarto: provide feedback when inspect fails

[aronatkins]

Given the Quarto document:

---
format: unsupported
---

This is a Quarto document that attempts to use an unrecognized format.

Running quarto inspect produces an error.

quarto inspect index.qmd
# => ERROR: Unknown format unsupported

However, when rsconnect::writeManifest() or rsconnect:deployApp() acts upon this file, there is no complaint.

rsconnect::writeManifest()

The manifest declares that it should be quarto-static but is created without a quarto block. Additionally, a set of R packages is inferred, as if it needs knitr/rmarkdown.

When rsconnect::deployApp() publishes to Posit Connect, the lack of a Quarto block produces an error:

── Deployment complete ───
✖ Deployment failed with error: Unsupported App Mode.

This type of error can happen when the document uses a new type of format but the Quarto installation does not support that format.

[ChaitaC]

Verified on rsconnect dev build

RemoteUsername: rstudio
RemoteRef: HEAD
RemoteSha: 2e59f9d56651189487e195a8140baebe580d3476
GithubRepo: rsconnect
GithubUsername: rstudio

Accurate feedback is provided when inspect fails

✔ Re-deploying "quarto1234-1" using "server: rsc.radixu.com / username: ChaitaTest"
Error in `quartoInspect()`:
! Failed to run `quarto inspect` against your content:
ERROR: Unknown format unsupported