[linter] Review linter setup (#3783)

- [2b395b9f] Fix command to lint markdown in `CONTRIBUTING.md`
- [fed4c86c] Re-activate JSDoc ESLint plugin and fix linting issues (As
far as I remember, we deactivated it when we upgraded to ESLint 9
because it was not compatible with it. But its now.)
- [a3d2064b] Refactor ESLint config to use `defineConfig` and
`globalIgnores` ([these are like new
defaults](https://eslint.org/blog/2025/03/flat-config-extends-define-config-global-ignores/))
- [a3d2064b] Replace `eslint-plugin-import` with
`eslint-plugin-import-x`
(https://github.com/es-tooling/module-replacements/blob/main/docs/modules/eslint-plugin-import.md)
- [86a185b6] Switch Stylelint config to flat format and simplify
Stylelint scripts (like we already did for ESLint and prettier)
  - [f5a2c541] Fix some typos

js/check_config.js

@@ -72,6 +72,10 @@ function checkConfigFile () {
 	}
 }
 
+/**
+ *
+ * @param {string} configFileName - The path and filename of the configuration file to validate.
+ */
 function validateModulePositions (configFileName) {
 	Log.info("Checking modules structure configuration ...");