dev-manual: Provided proper link title

In the "Enabling GObject Introspection Support" section, a link
existed to the "Known Issues" section further down in the
chapter.  The target of the link was missing and appeared as the
placeholder "xxx".  I put in the proper link.

(From yocto-docs rev: 8d0d1b2104f08e888075bc0ae0bed4f0ec2f4ea6)

Signed-off-by: Scott Rifenbark <srifenbark@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

documentation/dev-manual/dev-manual-common-tasks.xml

@@ -7129,7 +7129,8 @@
             This problem is solved with the OpenEmbedded build system by
             running the code through QEMU, which allows precisely that.
             Unfortunately, QEMU does not always work perfectly as mentioned
-            in the xxx section.
+            in the
+            "<link linkend='known-issues'>Known Issues</link>" section.
         </para>
 
         <section id='enabling-the-generation-of-introspection-data'>