Add new DSLs for checking that input file data is unique

Author: bjuric

docs/04-dsl.mdx

@@ -7833,7 +7833,7 @@ Since [v4.8.0](https://github.com/gwen-interpreter/gwen-web/releases/tag/v4.8.0)
   <summary class="dsl">
 
   ```gherkin
-  `<name> should be unique in the "<filepath>" file`
+  <name> should be unique in the "<filepath>" file
   ```
   <p>Checks that the current value of a field is unique in a CSV or JSON input file</p>
   </summary>