Fix dead link

Author: WardBrian

about/index.qmd

@@ -13,7 +13,7 @@ Stan is freedom-respecting, open-source software <span
 class="note">(new BSD core, some interfaces GPLv3)</span>.&nbsp; Stan
 is associated with NumFOCUS, a 501(c)(3) nonprofit supporting open code
 and reproducible science, through which you can [help support
-Stan](#support-stan).
+Stan](#help-fund-stan).
 
 ## Licensing