change file ref to App.js

lessons/03-js-tools/B-prettier.md

@@ -14,7 +14,7 @@ Need to tool around a bit with it before you trust it? [Go here][prettier-playgr
 
 Let's go integrate this into our project. It's _pretty_ easy (since I'm a dad now, I'm legally obligated to make this joke.)
 
-Either install Prettier globally `npm install --global prettier` or replace when I run `prettier` with (from the root of your project) `npx prettier`. From there, run `prettier script.js`. This will output the formatted version of your file. If you want to actually write the file, run `prettier --write script.js`. Go check script.js and see it has been reformatted a bit. I will say for non-JSX React, Prettier makes your code less readable. Luckily Prettier supports JSX! We'll get to that shortly.
+Either install Prettier globally `npm install --global prettier` or replace when I run `prettier` with (from the root of your project) `npx prettier`. From there, run `prettier src/App.js`. This will output the formatted version of your file. If you want to actually write the file, run `prettier --write src/App.js`. Go check App.js and see it has been reformatted a bit. I will say for non-JSX React, Prettier makes your code less readable. Luckily Prettier supports JSX! We'll get to that shortly.
 
 Prettier has a few configurations but it's mostly meant to be a tool everyone uses and doesn't argue/bikeshed about the various code style rules. [Here they are][prettier-options]. I just use it as is since I'm lazy. Prettier can also understand [flow][flow] and [TypeScript][ts].
 

lessons/03-js-tools/C-eslint.md

@@ -30,7 +30,7 @@ Create this file called `.eslintrc.json`.
 }
 ```
 
-This is a combination of the recommended configs of ESLint and Prettier. This will lint for both normal JS stuff as well as JSX stuff. Run `npx eslint script.js` now and you should see we have a few errors. Run it again with the `--fix` flag and see it will fix some of it for us! Go fix the rest of your errors and come back. Let's go add this to our npm scripts.
+This is a combination of the recommended configs of ESLint and Prettier. This will lint for both normal JS stuff as well as JSX stuff. Run `npx eslint src/App.js` now and you should see we have a few errors. Run it again with the `--fix` flag and see it will fix some of it for us! Go fix the rest of your errors and come back. Let's go add this to our npm scripts.
 
 ```json
 "lint": "eslint \"src/**/*.{js,jsx}\" --quiet",