document switch from Prism to Shiki (#777)

Author: ethanpalm

code.mdx

@@ -40,9 +40,7 @@ class HelloWorld {
 
 ## Syntax Highlighting
 
-Put the name of your programming language after the three backticks to get syntax highlighting.
-
-We use [Prism](https://prismjs.com/#supported-languages) for syntax highlighting. [Test Drive Prism](https://prismjs.com/test.html#language=markup) lists all the languages supported.
+Enable syntax highlighting by adding the language name after the opening backticks of a code snippet.
 
 ```java
 class HelloWorld {
@@ -62,6 +60,8 @@ class HelloWorld {
 ```
 ````
 
+We use [Shiki](https://shiki.style/guide) for syntax highlighting and support all available [languages](https://shiki.style/languages).
+
 ## Names
 
 Add a title after the programming language to set the name of your code example. The text can be anything as long as its all in one line.