Updates readme.txt some more

git-svn-id: https://plugins.svn.wordpress.org/prismatic/trunk@1974538 b8457f37-d9ea-0310-8a92-e5e31aec5664

readme.txt

@@ -169,7 +169,7 @@ Likewise, to indicate HTML as the language for a multi-line code snippet:
 
 Alternately, the language class may be placed on the <pre> tag, for example:
 
-	<pre class="language-html"><code>
+	<pre class="language-html"><code class="optional">
 		<table>
 			<tr>
 				<th>Name</th>
@@ -183,6 +183,8 @@ Alternately, the language class may be placed on the &lt;pre&gt; tag, for exampl
 		</table>
 	</code></pre>
 
+Note: in the previous example, ignore the `class="optional"` added to the code tag; it is used to prevent markdown from mangling the code example on this web page.
+
 Basically, the prefix of the class names (i.e., "lang-" or "language-") are the same for Prism.js and Highlight.js. The difference is the language identifier (e.g., "css" or "html") used to specify each language. Check out the following "About Prism.js" and "About Highlight.js" sections for more information.
 
 __Note:__ In addition to detecting the `language-` and `lang-` prefixes, Highlight.js also will try to auto-detect the language without it being specified. Plus as an option, you can enable the Highlight.js setting, "Support no-prefix class names" to enable use of language identifiers without any `language-` or `lang-` prefix.
@@ -320,7 +322,7 @@ So for example, to specify a code block as C++, you would write:
 	
 	Alternate: <pre class="language-cpp"><code class="optional">...</code></pre>
 
-Note: in the previous example, ignore the `class="optional"` added to the code tag (for the "Alternate" syntax); it is used to prevent markdown from mangling the code example.
+Note: in the previous example, ignore the `class="optional"` added to the code tag (for the "Alternate" syntax); it is used to prevent markdown from mangling the code example on this web page.
 
 To disable Prism.js syntax highlighting for any snippet, simply omit the language class. 
 
@@ -390,7 +392,7 @@ So for example, to specify a code block as C++, you would write:
 	
 	Alternate: <pre class="language-cpp"><code class="optional">...</code></pre>
 
-Note: in the previous example, ignore the `class="optional"` added to the code tag (for the "Alternate" syntax); it is used to prevent markdown from mangling the code example.
+Note: in the previous example, ignore the `class="optional"` added to the code tag (for the "Alternate" syntax); it is used to prevent markdown from mangling the code example on this web page.
 
 To disable Highlight.js syntax highlighting for any code block, add a class of `nohighlight`, like so: