Add yml example to single table inheritance

docs/en/reference/inheritance-mapping.rst

@@ -81,6 +81,8 @@ discriminator column is used.
 
 Example:
 
+.. configuration-block::
+
     .. code-block:: php
     
         <?php
@@ -105,6 +107,21 @@ Example:
             // ...
         }
 
+    .. code-block:: yaml
+    
+    MyProject\Model\Person:
+        type: entity
+        inheritanceType: SINGLE_TABLE
+        discriminatorColumn:
+            name: discr
+            type: string
+        discriminatorMap:
+            person: Person
+            employee: Employee
+            
+    MyProject\Model\Employee:
+        type: entity
+        
 Things to note: