fix(pat-validation): Put error messages always at the end of a group of inputs with the samne name.

Author: thet

src/pat/validation/documentation.md

@@ -89,10 +89,10 @@ In addition both the input element and its label will get an `warning` class.
 </label>
 ```
 
-Checkboxes and radio buttons are treated differently: if they are contained in a fieldset with class `checklist` error messages are added at the end of the fieldset.
+Checkboxes and radio buttons are treated differently: The error message is alywas set after the last element of the inputs with the same name.
 
 ```html
-<fieldset class="checklist radio">
+<fieldset>
     <label><input type="radio" name="radio" /> Strawberry</label>
     <label><input type="radio" name="radio" /> Banana</label>
     <label><input type="radio" name="radio" /> Raspberry</label>

src/pat/validation/validation.js

@@ -475,15 +475,9 @@ class Pattern extends BasePattern {
             this.error_template(validation_message)
         ).firstChild;
 
-        let fieldset;
-        if (input.type === "radio" || input.type === "checkbox") {
-            fieldset = input.closest("fieldset.pat-checklist");
-        }
-        if (fieldset) {
-            fieldset.append(error_node);
-        } else {
-            input.after(error_node);
-        }
+        // Put error messge after the erronous input or - in case of multiple
+        // inputs with the same name - after the last one of the group.
+        inputs.pop().after(error_node);
         input[KEY_ERROR_EL] = error_node;
 
         let did_disable = false;