Fully-qualify Javadoc reference so IDE does not try to add import statement.

If an IDE, such as Eclipse, adds an import for `ProjectCommand` in `Parser.java`, then
it will break the build because `Parser` does not depend on the `com.facebook.buck.cli`

Test Plan: Sandcastle builds.
diff --git a/src/com/facebook/buck/parser/Parser.java b/src/com/facebook/buck/parser/Parser.java
index 740c7ac..cc550ce 100644
--- a/src/com/facebook/buck/parser/Parser.java
+++ b/src/com/facebook/buck/parser/Parser.java
@@ -617,8 +617,8 @@
    * {@code android_binary}, but are defined in the same build files as the transitive
    * dependencies of an {@code android_binary}, this method is helpful in finding all of the
    * {@code project_config} rules needed to produce an IDE configuration to build said
-   * {@code android_binary}. See {@link ProjectCommand#predicate} for an example of such
-   * a {@link RawRulePredicate}.
+   * {@code android_binary}. See {@link com.facebook.buck.cli.ProjectCommand#predicate} for an
+   * example of such a {@link RawRulePredicate}.
   public synchronized List<BuildTarget> filterTargetsInProjectFromRoots(
       Iterable<BuildTarget> roots,