change number size of the vh and add a comment

src/client/styles/scss/_page_accessaries_modal.scss

@@ -6,11 +6,12 @@
   }
 
   .grw-tab-content-style {
-    max-height: 595vh;
+    max-height: 80vh;
   }
 }
 
-// revision-history diff
+// revision-history
+// to stay d2h-code-side-line-number in the revision history diff area
 .d2h-wrapper {
   position: relative;
 }