Add missing QHelp files

python/ql/src/Metrics/FLinesOfDuplicatedCodeCommon.qhelp

@@ -0,0 +1,35 @@
+<!DOCTYPE qhelp PUBLIC
+  "-//Semmle//qhelp//EN"
+  "qhelp.dtd">
+<qhelp>
+<overview>
+
+<p>
+This metric measures the number of lines in a file that are contained within a block that is duplicated elsewhere. These lines may include code, comments and whitespace, and the duplicate block may be in this file or in another file.
+</p>
+
+<p>
+A file that contains many lines that are duplicated within the code base is problematic
+for a number of reasons.
+</p>
+
+</overview>
+<include src="DuplicationProblems.qhelp" />
+
+<recommendation>
+
+<p>
+Refactor files with lots of duplicated code to extract the common code into
+a shared library or module.
+</p>
+
+</recommendation>
+<references> 
+
+
+<li>Wikipedia: <a href="http://en.wikipedia.org/wiki/Duplicate_code">Duplicate code</a>.</li>
+<li>M. Fowler, <em>Refactoring</em>. Addison-Wesley, 1999.</li>
+
+
+</references>
+</qhelp>