chore: remove eslint-env configuration comments

[MikeMcC399]

Situation

Several JavaScript source files in the src directory include the ESLint configuration comment:

/* eslint-env mocha */

This is no longer used in ESLint flat configurations, and will cause an error in ESLint 10.x and a warning in ESLint >=9.39.2.

See Configuration Migration Guide eslint-env Configuration Comments which says:

... when migrating from eslintrc to flat config, eslint-env configuration comments should be removed from all files.

This repo is already using an ESLint 9.x flat configuration and the mocha globals are provided by using mochaPlugin.configs.recommended.

Change

Remove the unused eslint-env configuration comment from source files in the src directory.

Verification

npm ci
npx eslint

Confirm no errors reported.

[MikeMcC399]

@AtofStryker

This is a non-urgent PR from last month, if you could take a look when convenient.

The latest version of ESLint 9.x (9.39.2) will flag this misconfiguration as a warning.