📚 Update live preview to myst-docutils 0.19 (#729)

Author: chrisjsewell

docs/live-preview.md

@@ -3,7 +3,7 @@ py-config:
   splashscreen:
     autoclose: true
   packages:
-    - myst-docutils==0.18
+    - myst-docutils==0.19
     - docutils==0.19
     - pygments
 ---
@@ -43,6 +43,8 @@ Hallo world!
 An admonition note!
 ```
 
+[Link to the heading](#heading-1)
+
 ## Math
 
 ```python
@@ -94,6 +96,7 @@ myst_enable_extensions:
 - colon_fence
 - deflist
 - dollarmath
+myst_heading_anchors: 2
 myst_highlight_code_blocks: true
 </textarea>
 ::::