Indentation issues in description lists with tagged regions

Reproduce the example using the description-list and tagged-region source shown in the issue, including stack-docs/docs/en/stack/index-landinall.adoc and glossary.asciidoc. Compare the generated nesting for the first leader index item with the local cluster item when building through Asciidoctor directly. Done means both items produce matching, correctly nested description-list output.

I think there is a bug in the indentations within description lists. For example, while playing with the Glossary in https://github.com/elastic/stack-docs/pull/1214, I noticed this:

Notice that the description of the first item in the "L" description list (in this case, "leader index") is not indented. [I don't think this bug is specific to our build tools, since the same thing happens when I build via Asciidoctor directly (e.g. asciidoctor stack-docs/docs/en/stack/index-landinall.adoc -r asciidoctor-diagram -a data-uri -D output/docs)].

The specific scenario where this seems to happen is when you're including content from tagged regions in the first item in the description list. Subsequent items have no such indentation issues. For example, here's an example of the source that hits this problem:

[[l-glos]] L::

[[glossary-leader-index]] leader index:::
+
--
include::{es-repo-dir}/glossary.asciidoc[tag=leader-index-def]
--

[[glossary-local-cluster]] local cluster:::
+
--
include::{es-repo-dir}/glossary.asciidoc[tag=local-cluster-def]
--

When you look at the output, you can see that the nesting of dl for the first item doesn't match the second item (i.e. it's nested incorrectly):

<dt>
--
  | <span class="term">
  | <a id="l-glos"></a> L
  | </span>
  | </dt>
  | <dd>
  | <div class="variablelist">
  | <dl class="variablelist">
  | <dt>
  | <span class="term">
  | <a id="glossary-leader-index"></a> leader index
  | </span>
  | </dt>
  | </dl>
  | </div>
  | <p>The source index for <a class="xref" href="terms.html#glossary-ccr">cross-cluster replication</a>. A leader index exists
  | on a remote cluster and is replicated to
  | <a class="xref" href="terms.html#glossary-follower-index">follower indices</a>.</p>
  | <div class="variablelist">
  | <dl class="variablelist">
  | <dt>
  | <span class="term">
  | <a id="glossary-local-cluster"></a> local cluster
  | </span>
  | </dt>
  | <dd>
  | <p>The cluster that pulls data from a <a class="xref" href="terms.html#glossary-remote-cluster">remote cluster</a> in cross-cluster search or cross-cluster replication.</p>
  | </dd>
  | </dl>
  | </div>
  | </dd>
  | <dt>

I am going to move away from using description lists this way in the glossary, since I find these indentation issues off-putting. I think it's worth investigating, however, in case this is a real bug that's worth fixing.