contents.css: Increase font size to 9-point Segoe UI.

The previous 8-point size looked fine in Firefox -- same as Windows GDI rendering or very close to it. But in Chrome, it looked too thin/light.

9-point looks a lot better in Chrome (but it's still lighter than Firefox).

ISHelp/Staging/contents.css

@@ -1,6 +1,6 @@
 /*
   Inno Setup
-  Copyright (C) 1997-2021 Jordan Russell
+  Copyright (C) 1997-2024 Jordan Russell
   Portions by Martijn Laan
   For conditions of distribution and use, see LICENSE.TXT.
 
@@ -8,8 +8,8 @@
 */
 
 BODY {
-	font-family: "Segoe UI", Tahoma, "Microsoft Sans Serif", "MS Sans Serif", sans-serif;
-	font-size: 66.667%;   /* 8pt (8/12) */
+	font-family: "Segoe UI", Tahoma, sans-serif;
+	font-size: 75%;   /* 9pt (12px/16px) */
 	margin: 0;
 	color: WindowText;
 	background-color: Window;
@@ -122,4 +122,4 @@ INPUT {
 	color: HighlightText;
 	background-color: Highlight;
 	outline-color: WindowText;   /* needed for focus rect to appear on Firefox (3.5) */
-}
+}