CONTRIBUTING.md: Amend linting note about npm script file path

[MaoShizhong]

Because

Currently, the linting guide has a note about running the npm run lint/fix:* scripts in the repo root else it won't find the correct config files. This is technically incorrect (which is my own mistake!) because npm scripts always run from the package root. Linting issues when users' terminals are in a subdirectory actually come from the file path, which they're often writing relative to their terminal location and not the package root, and has nothing to do with their current terminal location.

i.e. they can be inside ./javascript/testing_javascript and as long as they run with a path relative to root, they'll be fine e.g. npm run lint:lesson -- ./javascript/testing_javascript/test_basics.md

This PR

• Fixes linting warning to be about file path and not terminal cwd

Issue

N/A

Pull Request Requirements

• I have thoroughly read and understand The Odin Project curriculum contributing guide
• The title of this PR follows the location of change: brief description of change format, e.g. Intro to HTML and CSS lesson: Fix link text
• The Because section summarizes the reason for this PR
• The This PR section has a bullet point list describing the changes in this PR
• If this PR addresses an open issue, it is linked in the Issue section
• If any lesson files are included in this PR, they have been previewed with the Markdown preview tool to ensure it is formatted correctly
• If any lesson files are included in this PR, they follow the Layout Style Guide

[JoshDevHub]

Nice fix. And also thank you for teaching me something new! 😆