title: Doxygen doesn't generate documentation for enum not in class
body: <p>I have an enum inside of a namespace, but outside of a class. The enum is not being documented by Doxygen unless I enable <code>EXTRACT_ALL</code>, which extracts way too much unnecessary content.</p>
  
  <p>The place where it's used doesn't link the enum (it does if I use <code>EXTRACT_ALL</code>). The enum and its members are documented (and the documentation shows up as expected with <code>EXTRACT_ALL</code>). Without that setting, the enum doesn't show up in the documentation anywhere.</p>
  
  <p>Is there some other setting that I could use that would be more precise than using <code>EXTRACT_ALL</code>?</p>
  
  <p>I currently have <code>EXTRACT_PRIVATE</code>, <code>EXTRACT_PACKAGE</code>, <code>EXTRACT_STATIC</code>, <code>EXTRACT_LOCAL_CLASSES</code>, and <code>EXTRACT_ANON_NSPACES</code> enabled, with the various <code>HIDE_*</code> settings being off.</p>