docs: added description and example usage for auto scroll feature (#83)

guide/syntax.md

@@ -102,6 +102,8 @@ function add(
 //```
 ~~~
 
+This will first highlight `a: Ref<number> | number` and `b: Ref<number> | number`, and then `return computed(() => unref(a) + unref(b))` after one click, and lastly, the whole block. Learn more in the [clicks animations guide](/guide/animations).
+
 To skip highlighting any lines, you can set the line number to `0`. For example
 
 ~~~ts {0}
@@ -115,7 +117,21 @@ function add(
 //```
 ~~~
 
-This will first highlight `a: Ref<number> | number` and `b: Ref<number> | number`, and then `return computed(() => unref(a) + unref(b))` after one click, and lastly, the whole block. Learn more in the [clicks animations guide](/guide/animations).
+If the code doesn't fit into one slide, you can pass an extra maxHeight option which will set fixed height
+and enable scrolling
+
+~~~ts {2|3|7|12}
+//```ts {2|3|7|12} {maxHeight:'100'}
+function add(
+  a: Ref<number> | number,
+  b: Ref<number> | number
+) {
+  return computed(() => unref(a) + unref(b))
+}
+/// ...as many lines as you want
+const c = add(1, 2)
+//```
+~~~
 
 ### Monaco Editor