Fix region exclusion with multiple lines.

Added the 's' modifier so that the regex that detects not-to-be-linked
regions that span several lines (e.g., multiline <pre></pre> section).

LinkTitles.body.php

@@ -147,7 +147,7 @@
 				'style=".+?"|class=".+?"|' .                // styles and classes (e.g. of wikitables)
 				'\[' . $urlPattern . '\s.+?\]|'. $urlPattern .  '(?=\s|$)|' . // urls
 				'(?<=\b)\S+\@(?:\S+\.)+\S+(?=\b)' .        // email addresses
-				')/i';
+				')/is';
 
 			// Build a blacklist of pages that are not supposed to be link 
 			// targets. This includes the current page.