fix incorrect code language case

contributing/development.md

@@ -12,7 +12,7 @@ You'll need Node.js to run the site. Check the version in `package.json`. To ins
 
 Once you've installed Node.js (which includes the popular `npm` package manager), open Terminal and run the following:
 
-```sh
+```shell
 git clone https://github.com/github/docs
 cd docs
 npm ci

contributing/node-versions.md

@@ -16,13 +16,13 @@ When updating to a new Node.js version, consider the following files:
 
 If you're using macOS, run this command to get the latest:
 
-```sh
+```shell
 brew upgrade nodenv node-build
 ```
 
 If you see a warning like this one, run the suggested command:
 
-```sh
+```shell
 # You should change the ownership of these directories to your user.
 sudo chown -R $(whoami) /usr/local/sbin
 ```
@@ -31,19 +31,19 @@ If you're using another operating system, or did not use Homebrew to install nod
 
 To install Node.js and make it your default version, run this command:
 
-```sh
+```shell
 # Set VERSION= based on package.json#engines
 nodenv install $VERSION && nodenv global $VERSION
 ```
 
 You may sometimes see a warning when running npm scripts with nodenv:
 
-```sh
+```shell
 npm WARN lifecycle The node binary used for scripts is [...] but npm is using [...]
 ```
 
 This is due to nodenv's overriding behavior. To silence this harmless warning, the [nodenv docs](https://github.com/nodenv/nodenv/wiki/FAQ#npm-warning-about-mismatched-binaries) recommend running the following command from any directory:
 
-```sh
+```shell
 npm config set scripts-prepend-node-path auto
 ```

contributing/videos.md

@@ -126,7 +126,7 @@ Add a link to the article with a video's transcript in the description of the vi
 
 In any content with an embedded video, add a `product_video_transcript` property below the `product_video` property in the YAML frontmatter. The value of `product_video_transcript` is a link to the transcript article in the `video-transcripts` directory.
 
-```YAML
+```yaml
 title: Example product landing page
 product_video: 'https://www.youtube-nocookie.com/embed/URL'
 product_video_transcript: /content/video-transcripts/TRANSCRIPT-TITLE