Enhance the code blocks docs

Describe what the `[1-2|3|4]` is doing

Add link to reveal.js code docs

Author: axelson

docs/content/basic-syntax/codeBlocks.md

@@ -4,14 +4,19 @@ description = ""
 weight = 10
 +++
 
+As you go to the next slide this code block will first highlight lines 1-2, then line 3, then finally line 4.
+
+Note: the `js` indicates that this code should be highlighted as javascript
 ```md
 
 ```js [1-2|3|4]
-    let a = 1;
-    let b = 2;
-    let c = x => 1 + 2 + x;
-    c(3);
-    ```
+let a = 1;
+let b = 2;
+let c = x => 1 + 2 + x;
+c(3);
+```
 ```
 
-![CodeBlock](https://mszturc.github.io/obsidian-advanced-slides/images/codeblock.png)
+![CodeBlock](https://mszturc.github.io/obsidian-advanced-slides/images/codeblock.png)
+
+For the full documentation about what you can do with code blocks see: https://revealjs.com/code/