cove_rdls/templates/cove_rdls/validation_table.html: Fix first links …

…error message

cove_rdls/templates/cove_rdls/validation_table.html

@@ -22,7 +22,9 @@
 <tr>
   <td>
     <p>
-      {% if errors.0.validator == "const" and errors.0.validator_value == "describedby" %}
+      {% if errors.0.validator == "const" and errors.0.validator_value == "describedby" and errors.0.path|links_rel_first %}
+        <strong><code>{{ errors.0.path_ending }}</code> is not 'describedby'. The first item in the <code>links</code> array must be a link to the canonical URL of the RDLS JSON schema with relation type 'describedby'.</strong>
+      {% elif errors.0.validator == "const" and errors.0.validator_value == "describedby" %}
         <strong><code>{{ errors.0.path_ending }}</code> does not match the regex <code>{{ errors.0.validator_value }}</code>. With the exception of the first item in the links array, the value of <code>{{ errors.0.path_ending }}</code> must not be 'describedby'.</strong>
       {% elif errors.0.validator == "const" %}
         <strong><code>{{ errors.0.path_ending}}</code> does not match constant specified in schema. The value must be {{ errors.0.validator_value }}.</strong>
@@ -49,7 +51,8 @@
 	<strong><code>{{ value }}</code> does not match any code. <code>{{ value }}</code> must match a code from the codelist specified in the schema.</strong>
         {% endwith %}
       {% elif errors.0.validator == "pattern" and errors.0.path|links_rel_first %}
-        <strong><code>{{ errors.0.path_ending }}</code> is not 'describedby'. The first item in the <code>links</code> array must be a link to the canonical URL of the RDLS JSON schema with relation type 'describedby'.</strong>
+        <strong><code>{{ errors.0.path_ending }}</code> is not 'describedby'. The first item in the <code>links</code> array must be a link 
+to the canonical URL of the RDLS JSON schema with relation type 'describedby'.</strong>
       {% elif errors.0.validator == "pattern" and errors.0.path|links_rel_subsequent %}
         <strong><code>{{ errors.0.path_ending }}</code> is 'describedby'. With the exception of the first item in the <code>links</code> array, the value of <code>{{ errors.0.path_ending }}</code> must not be 'describedby'.</strong>
       {% elif errors.0.validator == "pattern" %}