adds additional output to linting tool for formatting failure case

[indirectlylit]

Summary

While working on learningequality/kolibri-design-system#358 I was confused why sometimes linting would fail without any actionable error:

~/Projects/le/design-system main* ⇡ 6s
❯ yarn lint
yarn run v1.22.18
$ kolibri-tools lint --pattern '**/*.vue' -i ,'**/node_modules/**','**/.nuxt/**','**/dist/**','**/lib/KIcon/precompiled-icons/**','**/lib/keen/**','**/docs/environment.js','**/docs/jsdocs.js'
error Command failed with exit code 1.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.

Running yarn lint-fix ended up reformatting a file, so it was something to do with prettier or eslint.

I believe this output should give more actionable information about why the lint command might be failing.

Reviewer guidance

• Modify a file such that it might be reformatted by prettier, e.g. < div >hello</div>
• Run lint-frontend without and without this patch
• With the patch it should show what file is causing issues

Testing checklist

• Contributor has fully tested the PR manually
• If there are any front-end changes, before/after screenshots are included
• Critical user journeys are covered by Gherkin stories
• Critical and brittle code paths are covered by unit tests

PR process

• PR has the correct target branch and milestone
• PR has 'needs review' or 'work-in-progress' label
• If PR is ready for review, a reviewer has been added. (Don't use 'Assignees')
• If this is an important user-facing change, PR or related issue has a 'changelog' label
• If this includes an internal dependency change, a link to the diff is provided

Reviewer checklist

• Automated test coverage is satisfactory
• PR is fully functional
• PR has been tested for accessibility regressions
• External dependency files were updated if necessary (yarn and pip)
• Documentation is updated
• Contributor is in AUTHORS.md

[github-actions]

Build Artifacts

Asset type	Download link
PEX file	kolibri-0.16.0.dev0_git.20220903232025.pex
Unsigned Windows installer	kolibri-0.16.0.dev0+git.20220903232025-unsigned.exe
Debian Package	kolibri_0.16.0.dev0+git.20220903232025-0ubuntu1_all.deb
Mac Installer (DMG)	kolibri-0.16.0.dev0+git.20220903232025-0.3.0.dmg
Source Tarball	kolibri-0.16.0.dev0+git.20220903232025.tar.gz
WHL file	kolibri-0.16.0.dev0+git.20220903232025-py2.py3-none-any.whl

[rtibbles]

Flagging that I may neglect to merge this in favour of current WIP to upgrade eslint and address #5410 - I'll see whether it conflicts with my current work or not.

[indirectlylit]

sure, @MisRob or you can just make this update there and close this PR

[indirectlylit]

Sorry for the noise @MisRob I see you filed the issue, and @rtibbles is working on the PR. my bad

[rtibbles]

OK, I think this was probably caused by either eslint or stylelint reformatting a file, but prettier not? Either way, I think this should be covered in my changes.

[MisRob]

No worries, always happy to hear from you in any way, @indirectlylit ;)

[MisRob]

Thanks for another contribution

[rtibbles]

Superseded by #9698