Describe the bug
Brief comments in a base class result in searchdata.xml containing the field "text" N times where N is the number of classes derived from the base class.
This doesn't seem like a big issue in this small example. However in my huge project with a large class hierarchy this results in getting huge fields which is also visible in the search results on the website using the external search engine.

To Reproduce
There are three c++ classes defined:
ClassA, ClassB and ClassC where ClassB and ClassC are both derived from ClassA.
ClassA has a method myMethod with a brief comment containing the text "This is a brief comment".
Generate using the following settings:

JAVADOC_AUTOBRIEF = YES
EXTERNAL_SEARCH = YES

the attached zip contains a minimal example to replicate.

As a result I get an entry in searchdata:

<doc>
  <field name="type">function</field>
  <field name="name">ClassA::myMethod</field>
  <field name="args">(int arg)</field>
  <field name="url">class_class_a.html#a464f8f980ac6ef91714a60d2bd906203</field>
  <field name="keywords">myMethod ClassA::myMethod ClassA</field>
  <field name="text">This is a brief comment This is a brief comment This is a brief comment</field>
</doc>

Expected behavior
As a result I should get an entry in searchdata like:

<doc>
  <field name="type">function</field>
  <field name="name">ClassA::myMethod</field>
  <field name="args">(int arg)</field>
  <field name="url">class_class_a.html#a464f8f980ac6ef91714a60d2bd906203</field>
  <field name="keywords">myMethod ClassA::myMethod ClassA</field>
  <field name="text">This is a brief comment</field>
</doc>

Version
Tested with current master but got the same behaviour with version 1.13.x and 1.14.x
Running on linux or windows results in the same behaviour.

searchdata.zip