eslint: Add @wordpress/eslint-plugin/i18n ruleset

[yuliyan]

Changes proposed in this Pull Request

• Add @wordpress/eslint-plugin/i18n ruleset to root eslint config
• Disable @wordpress/i18n-text-domain rule, because we use __i18n_text_domain__ global constant in packages instead of string literals.

Testing instructions

• Checkout the branch locally and yarn install
• Run yarn eslint on a file that is known not to fulfil the rules from @wordpress/eslint-plugin/i18n and confirm it's reporting the lint errors, e.g. packages/domain-picker/src/domain-picker/suggestion-item.tsx

[matticbot]

Test live: https://calypso.live/?branch=add/wordpress-eslint-plugin-i18n-ruleset

[scinos]

I'm re-running Check code style for branches (Calypso) with the option to lint all the files, so we can compare with trunk.

[matticbot]

This PR does not affect the size of JS and CSS bundles shipped to the user's browser.

Generated by performance advisor bot at iscalypsofastyet.com.

[akirk]

Looks like this revealed quite a number of errors:

[simison]

I'll ping the teams potentially to help here:

• @Automattic/shilling: client/my-sites/checkout/*
• @Automattic/cylon : apps/editing-toolkit-plugin/dotcom-fse/* & apps/editing-toolkit-plugin/global-styles/*
• @Automattic/luna : client/landing/gutenboarding/*, packages/plans-grid/*, packages/domain-picker/*, client/components/language-picker/*

[sirbrillig]

Thanks for the ping! Should we fix the reported issues in this PR or is the intent that we just be aware of them? All the ones in checkout are @wordpress/i18n-translator-comments, so I've made a PR for them here: #49372

[ciampo]

@Automattic/luna : client/landing/gutenboarding/*, packages/plans-grid/*, packages/domain-picker/*, client/components/language-picker/*

We're actively editing most of these files in currently open PRs — what is not fixed there, we can add to this PR (or create a separate PR, whatever works best)

[yuliyan]

I think fixing them in a separate PR, similarly to #49372, would be better. When the fixes land on trunk, I'll rebase this PR to verify lint errors are gone.

[ciampo]

I think fixing them in a separate PR, similarly to #49372, would be better. When the fixes land on trunk, I'll rebase this PR to verify lint errors are gone.

Opened #49400 — will let you know once it's approved and merged

[ciampo]

@yuliyan #49400 has been merged — All errors that were "assigned" to team Luna should be solved 🤞

[yuliyan]

All of the existing lint problems have been resolved with #49372, #49400, #49526, #50190, #50191. The PR is ready to be merged.