Update syntax comment color

Author: rich-iannone

great_docs/assets/great-docs.scss

@@ -3047,7 +3047,7 @@ body.quarto-dark {
     --gd-syn-keyword: #c792ea;
     --gd-syn-string: #c3e88d;
     --gd-syn-number: #f78c6c;
-    --gd-syn-comment: #697098;
+    --gd-syn-comment: #8891b3;
     --gd-syn-function: #82aaff;
     --gd-syn-builtin: #ffcb6b;
 }