Improved language used in markdown code blocks. (#6419)

* Improved language used in code blocks.

docusaurus/docs/adding-a-sass-stylesheet.md

@@ -12,7 +12,7 @@ Following this rule often makes CSS preprocessors less useful, as features like
 
 To use Sass, first install `node-sass`:
 
-```bash
+```sh
 $ npm install node-sass --save
 $ # or
 $ yarn add node-sass

docusaurus/docs/adding-custom-environment-variables.md

@@ -95,7 +95,7 @@ set "REACT_APP_NOT_SECRET_CODE=abcdef" && npm start
 
 ### Linux, macOS (Bash)
 
-```bash
+```sh
 REACT_APP_NOT_SECRET_CODE=abcdef npm start
 ```
 

docusaurus/docs/adding-typescript.md

@@ -9,7 +9,7 @@ title: Adding TypeScript
 
 To start a new Create React App project with [TypeScript](https://www.typescriptlang.org/), you can run:
 
-```bash
+```sh
 npx create-react-app my-app --typescript
 
 # or
@@ -19,7 +19,7 @@ yarn create react-app my-app --typescript
 
 To add [TypeScript](https://www.typescriptlang.org/) to a Create React App project, first install it:
 
-```bash
+```sh
 npm install --save typescript @types/node @types/react @types/react-dom @types/jest
 
 # or

docusaurus/docs/analyzing-the-bundle-size.md

@@ -33,7 +33,7 @@ Then in `package.json`, add the following line to `scripts`:
 Then to analyze the bundle run the production build then run the analyze
 script.
 
-```
+```sh
 npm run build
 npm run analyze
 ```

docusaurus/docs/debugging-tests.md

@@ -20,7 +20,7 @@ Add the following to the `scripts` section in your project's `package.json`
 
 Place `debugger;` statements in any test and run:
 
-```bash
+```sh
 $ npm run test:debug
 ```
 
@@ -42,7 +42,7 @@ Debugging Jest tests is supported out of the box for [Visual Studio Code](https:
 
 Use the following [`launch.json`](https://code.visualstudio.com/docs/editor/debugging#_launch-configurations) configuration file:
 
-```
+```json
 {
   "version": "0.2.0",
   "configurations": [

docusaurus/docs/deployment.md

@@ -209,7 +209,7 @@ Then run the `firebase init` command from your project’s root. You need to cho
 
 IMPORTANT: you need to set proper HTTP caching headers for `service-worker.js` file in `firebase.json` file or you will not be able to see changes after first deployment ([issue #2440](https://github.com/facebook/create-react-app/issues/2440)). It should be added inside `"hosting"` key like next:
 
-```
+```json
 {
   "hosting": {
     ...

docusaurus/docs/proxying-api-requests-in-development.md

@@ -17,7 +17,7 @@ Such setup is **not** required. However, if you **do** have a setup like this, i
 
 To tell the development server to proxy any unknown requests to your API server in development, add a `proxy` field to your `package.json`, for example:
 
-```js
+```json
   "proxy": "http://localhost:4000",
 ```
 
@@ -74,7 +74,7 @@ You can use this feature in conjunction with the `proxy` property in `package.js
 
 First, install `http-proxy-middleware` using npm or Yarn:
 
-```bash
+```sh
 $ npm install http-proxy-middleware --save
 $ # or
 $ yarn add http-proxy-middleware

docusaurus/docs/running-tests.md

@@ -321,7 +321,7 @@ Popular CI servers already set the environment variable `CI` by default but you
 1. Following the [Travis Getting started](https://docs.travis-ci.com/user/getting-started/) guide for syncing your GitHub repository with Travis. You may need to initialize some settings manually in your [profile](https://travis-ci.org/profile) page.
 1. Add a `.travis.yml` file to your git repository.
 
-```
+```yaml
 language: node_js
 node_js:
   - 8
@@ -366,11 +366,11 @@ set CI=true&&npm run build
 
 #### Linux, macOS (Bash)
 
-```bash
+```sh
 CI=true npm test
 ```
 
-```bash
+```sh
 CI=true npm run build
 ```
 

docusaurus/docs/using-https-in-development.md

@@ -26,7 +26,7 @@ set HTTPS=true&&npm start
 
 ### Linux, macOS (Bash)
 
-```bash
+```sh
 HTTPS=true npm start
 ```