Add stub for treat-blank-as-empty config

Signed-off-by: Jarno Elovirta <[email protected]>

parameters/configuration-properties-file.dita

@@ -73,6 +73,14 @@
         configuration in the <codeph>dost-configuration.jar</codeph> file when the plug-in integration process runs. The
         following properties are typically set in this file:</p>
       <parml>
+        <plentry id="compatibility-keyref-treat-blank-as-empty">
+          <pt><parmname>compatibility.keyref.treat-blank-as-empty</parmname></pt>
+          <pd>
+            <p>Enables compatibility mode that incorrectly processes key references that have only whitespace
+            content.</p>
+            <note type="warning">This property can only be set in
+                <filepath>configuration.properties</filepath>.</note></pd>
+        </plentry>
         <plentry id="default-cascade">
           <pt><parmname>default.cascade</parmname></pt>
           <pd>