Upgrade eslint (#1014)

It's apparently forced now to use the eslint.config.js instead of
.eslintrc

It got more strict with requiring the underscore on unused vars like
`catch(_err)` , but that was all

Closes #1012
Closes #995
Closes #992

## Launch Checklist

<!-- Thanks for the PR! Feel free to add or remove items from the
checklist. -->


 - [ ] Briefly describe the changes in this PR.
 - [ ] Link to related issues.
- [ ] Include before/after visuals or gifs if this PR includes visual
changes.
 - [ ] Write tests for all new functionality.
 - [ ] Add an entry to `CHANGELOG.md` under the `## main` section.

i18next-parser.config.ts

@@ -10,7 +10,7 @@ export default {
   keySeparator: false,
   namespaceSeparator: false,
 
-  defaultValue: (locale, ns, key) => {
+  defaultValue: (_locale, _ns, _key) => {
     // The default value is a string that indicates that the string is not translated.
     return '__STRING_NOT_TRANSLATED__';
   }