AttributeSource api has broken documentation due to java generics bug [LUCENE-4010]

There seems to be a javadocs generation bug, whereby generic type params are not properly escaped. So if you use <A> as a type param (which we do in AttributeSource.java), it produces invalid HTML. The bug seems to be fixed in java 7...

You can see the bug here (search for "after adding"):

http://lucene.apache.org/core/old_versioned_docs/versions/3_5_0/api/all/org/apache/lucene/util/AttributeSource.html

The <A> generic type is gone, and that closing paren is red but should be blue.

The 3.6.0 javadocs are OK because we used java7 to generate them...

I think we should avoid <A> to workaround it until we are on java 7...

---
Migrated from [LUCENE-4010](https://issues.apache.org/jira/browse/LUCENE-4010) by Michael McCandless (@mikemccand), updated Apr 23 2012