Fix Markdown reference

Author: Matistjati

spec/2023-07-draft.md

@@ -503,7 +503,7 @@ Still, a reasonable effort shall be made to ensure that CommonMark-compliant sta
 Additionally, the following extensions shall be supported:
 
 - All [MathJax-supported TeX commands](https://docs.mathjax.org/en/latest/input/tex/macros/index.html) within inline (`$ $`) and display (`$$ $$`) math mode.
-- Tables and footnotes as described in CommonMark's [extended syntax](https://www.markdownguide.org/extended-syntax/).
+- Tables and footnotes as described in Markdown Guide's [extended syntax](https://www.markdownguide.org/extended-syntax/).
 
 ## Attachments