Save category description in Moodle XML import/export

What is not saved?

At this format of import/export in not saved:

1. description of the imported/exported category,

2. description of parental category(categories).

Current XML structure

<question type="category">
 <category>
  <text> $course$ / [ $parent category name$ / ] $current category name$ </text>
 </category>
</question>

The amount of block [ $parent category name$ / ] can be more or equally to zero.

Proposed XML structure

If current category has parent then

<question type="category">
 <category name="$parent category name$">
  <description>Description of category</description>
   <category name="$current category name$">
    <description>Description of category</description>
   </category>
 </category>
</question>

else

<question type="category">
 <category name="$current category name$">
  <description>Description of category</description>
 </category>
</question>