Add Gherkin page to docs

docs/_data/sidebars/pmd_sidebar.yml

@@ -382,6 +382,9 @@ entries:
     - title: HTML
       url: /pmd_languages_html.html
       output: web, pdf
+    - title: Gherkin
+      url: /pmd_languages_gherkin.html
+      output: web, pdf
   - title: Developer Documentation
     output: web, pdf
     folderitems:

docs/pages/pmd/languages/gherkin.md

@@ -0,0 +1,15 @@
+---
+title: Gherkin 
+permalink: pmd_languages_gherkin.html
+---
+
+The [Gherkin](https://cucumber.io/docs/gherkin/) language is used to define test cases for the [Cucumber](https://cucumber.io/) testing tool for behavior-driven development. The Gherkin syntax is designed to be 
+non-technical, making it human-readable for a wide audience.
+
+## Support in PMD
+Starting from version 6.48.0, Gherkin support was added to CPD.
+
+### Limitations
+- Support for Gherkin only extends to CPD to detect code duplication in Cucumber test cases. 
+- While Gherkin keywords have been translated into various
+languages, CPD currently supports only the English version of the Gherkin language.