xml:id title --> chapter

Doc/Tdoc/projects.xml

 <?xml version="1.0" encoding="UTF-8"?>
-<chapter version="5.0" xmlns="http://docbook.org/ns/docbook"
+<chapter version="5.0" xml:id="tdocChapProjects"
+         xmlns="http://docbook.org/ns/docbook"
          xmlns:xlink="http://www.w3.org/1999/xlink"
          xmlns:xi="http://www.w3.org/2001/XInclude"
          xmlns:svg="http://www.w3.org/2000/svg"
          xmlns:m="http://www.w3.org/1998/Math/MathML"
          xmlns:html="http://www.w3.org/1999/xhtml"
          xmlns:db="http://docbook.org/ns/docbook">
-  <title xml:id="tdocChapProjects">Possible projects</title>
+  <title>Possible projects</title>
 
   <orderedlist>
     <listitem>