You can choose from several languages to insert formatted code in your post.
To insert code in a post, a reply or when editing an existing reply:
1. Click the three vertical dots to expand the editorial toolbar of your post, comment, or reply.
2. Select the Insert Code icon </>.
2. Select your code language.
3. Enter your code.
4. Click Ok.
Collapsed Text Editor
Expanded Text Editor
You are missing step zero, click on the 3 dots to expand the available buttons so you can actually see the insert code button hat you refer to on step 1!