Linting rule to check formatting of translation strings

[KshitijThareja]

Summary

This PR introduces a new linting rule to check if the translation strings defined in $trs and createTranslator functions are properly formatted, i.e, they have a specific shape and their properties are of a specific datatype.

Sample error

References

Closes #11301

Reviewer guidance

To test these changes:

1. Modify any translation string defined in a Vue or JS file so that it has an improper format.
2. Run the linting command: yarn run lint-frontend.
3. You'll see the particular translation string's name logged in the terminal.

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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

[KshitijThareja]

Hi @AlexVelezLl 👋🏻
I've covered most of the requirements for this issue. I couldn't figure out how to add a check to ensure that the message property is of type string as there are some message keys containing variables, which gets classified as 'undefined' when checked for their type. Other than that, everything else works as expected.
Also, please mention if you have any other suggestions that you'd like to be incorporated in the code. I'll be happy to work on them :)

[github-actions]

Build Artifacts

Asset type	Download link
PEX file	kolibri-0.16.0b10.dev0_git.56.gf87593a9.pex
Windows Installer (EXE)	kolibri-0.16.0b10.dev0+git.56.gf87593a9-unsigned.exe
Debian Package	kolibri_0.16.0b10.dev0+git.56.gf87593a9-0ubuntu1_all.deb
Mac Installer (DMG)	kolibri-0.16.0b10.dev0+git.56.gf87593a9-0.3.0.dmg
Android Package (APK)	kolibri-0.16.0b10.dev0+git.56.gf87593a9-0.1.0-debug.apk
TAR file	kolibri-0.16.0b10.dev0+git.56.gf87593a9.tar.gz
WHL file	kolibri-0.16.0b10.dev0+git.56.gf87593a9-py2.py3-none-any.whl

[rtibbles]

This looks great, thanks @KshitijThareja and it looks like you have discovered an existing issue here! https://github.com/learningequality/kolibri/blob/release-v0.16.x/kolibri/plugins/learn/assets/src/views/ExploreLibrariesPage/index.vue#L176

Could you correct continue to context here, so that the linting passes and we can merge this?

[KshitijThareja]

Sure @rtibbles. I'll make the changes 👍🏻

[rtibbles]

Thank you @KshitijThareja great work!

[KshitijThareja]

Welcome @rtibbles 😄
It was personally a great experience working on this issue. Looking forward to contribute further 👍🏻