Add text examples to CSS syntax highlighting.

src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Highlighting/Resources/CSS-Mode.xshd

@@ -1,13 +1,12 @@
 <SyntaxDefinition name="CSS" extensions=".css" xmlns="http://icsharpcode.net/sharpdevelop/syntaxdefinition/2008">
-	<Color name="Comment" foreground="Gray" />
-	<Color name="String" foreground="Green" />
-	<Color name="Selector" foreground="DarkBlue" fontWeight="bold" />
-	<Color name="Class" foreground="DarkMagenta" />
-	<Color name="Property" foreground="Red"/>
-	<Color name="Value" foreground="Blue" />
-	<Color name="Default" foreground="Pink" />
-	<Color name="CurlyBraces" foreground="Black" />
-	<Color name="Colon" foreground="Black" />
+	<Color name="Comment" foreground="Gray" exampleText="/* comment */" />
+	<Color name="String" foreground="Green" exampleText="body { background: url(&quot;image.png&quot;) }" />
+	<Color name="Selector" foreground="DarkBlue" fontWeight="bold" exampleText="div p" />
+	<Color name="Class" foreground="DarkMagenta" exampleText="#para" />
+	<Color name="Property" foreground="Red" exampleText="p { color: red; }" />
+	<Color name="Value" foreground="Blue" exampleText="p { color: red; }" />
+	<Color name="CurlyBraces" foreground="Black" exampleText="{ }" />
+	<Color name="Colon" foreground="Black" exampleText=":" />
 	<RuleSet ignoreCase="true">
 		<Span color="Comment" multiline="true">
 			<Begin>/\*</Begin>