docs: document how to use tab blocks

Author: fhennig

modules/contributor/nav.adoc

@@ -11,6 +11,7 @@
 ** xref:docs/contributing-documentation.adoc[]
 *** xref:docs/overview.adoc[]
 *** xref:docs/style-guide.adoc[]
+*** xref:docs/using-tab-blocks.adoc[]
 *** xref:docs/backporting-changes.adoc[]
 *** xref:docs/releasing-a-new-version.adoc[]
 *** xref:docs/troubleshooting-antora.adoc[]

modules/contributor/pages/docs/using-tab-blocks.adoc

@@ -0,0 +1,27 @@
+= Using tab blocks
+:asciidoctor-tabs-gh: https://github.com/asciidoctor/asciidoctor-tabs
+
+The {asciidoctor-tabs-gh}[`asciidoctor/tabs`] extension is installed, so you can use tab blocks.
+An example can be found in the xref:management:stackablectl:installation.adoc[stackablectl installation instructions].
+
+== Syntax example
+
+[,asciidoc]
+----
+[tabs]
+====
+Tab A:: Contents of Tab A.
+
+Tab B::
++
+Contents of Tab B.
+
+Tab C::
++
+--
+Contents of Tab C.
+
+Contains more than one block.
+--
+====
+----