Fix javadoc of TooLargeObjectInPackException

The API exception should have the same javadoc like the internal
exception org.eclipse.jgit.errors.TooLargeObjectInPackException

Change-Id: Ia7508c77609e53c8e808412ac523a93194648e49
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

org.eclipse.jgit/src/org/eclipse/jgit/api/errors/TooLargeObjectInPackException.java

@@ -38,7 +38,8 @@
 package org.eclipse.jgit.api.errors;
 
 /**
- * Exception thrown when the server rejected a too large pack
+ * Exception thrown when PackParser finds an object larger than a predefined
+ * limit
  *
  * @since 4.4
  */