Rename mapping from parent to parentId

The attribute `parentId` is used in Craft to signify the value of the
parent element, if any.  Therefore, the mapping handle should also be
`parentId`.

This patch changes the mapping handle from `parent` into `parentId`.
This allows the comparison code to properly verify that an existing
parent already exists.  Without this patch the current comparison will
use the `parent` property that does not exist in a Craft entry.  This
should have been `parentId` which does exist.

Note that this patch is *not* backwards compatible, all imports that
have been configured with a parent using handle `parent` must
reconfigure the parent so it uses the renamed handle `parentId`.

Perhaps it is worth the time to create a migration for this?

src/elements/Category.php

@@ -132,7 +132,7 @@ public function afterSave($data, $settings): void
      * @throws ElementNotFoundException
      * @throws Exception
      */
-    protected function parseParent($feedData, $fieldInfo): ?int
+    protected function parseParentId($feedData, $fieldInfo): ?int
     {
         $value = $this->fetchSimpleValue($feedData, $fieldInfo);
         $default = DataHelper::fetchDefaultArrayValue($fieldInfo);

src/elements/Entry.php

@@ -224,7 +224,7 @@ protected function parseExpiryDate($feedData, $fieldInfo): DateTime|bool|array|C
      * @throws ElementNotFoundException
      * @throws Exception
      */
-    protected function parseParent($feedData, $fieldInfo): ?int
+    protected function parseParentId($feedData, $fieldInfo): ?int
     {
         $value = $this->fetchSimpleValue($feedData, $fieldInfo);
         $default = DataHelper::fetchDefaultArrayValue($fieldInfo);

src/templates/_includes/elements/categories/map.html

@@ -23,7 +23,7 @@
 }, {
     type: 'categories',
     name: 'Parent',
-    handle: 'parent',
+    handle: 'parentId',
     instructions: 'Select a parent category to import these categories under.'|t('feed-me'),
     default: {
         type: 'elementselect',

src/templates/_includes/elements/entries/map.html

@@ -30,7 +30,7 @@
     {% set fields = fields|push({
         type: 'entries',
         name: 'Parent',
-        handle: 'parent',
+        handle: 'parentId',
         instructions: 'Select a parent entry to import these entries under.'|t('feed-me'),
         default: {
             type: 'elementselect',