Issue #3206932 by Matroskeen, quietone, alexpott: Rename targetEntityType...

Issue #3206932 by Matroskeen, quietone, alexpott: Rename targetEntityType constant in d6_view_mode migration to simplify source plugin

(cherry picked from commit bd2a1eab)

core/modules/node/migrations/d6_view_modes.yml

@@ -6,7 +6,7 @@ migration_tags:
 source:
   plugin: d6_view_mode
   constants:
-    targetEntityType: node
+    entity_type: node
     status: true
 process:
   mode:
@@ -33,7 +33,7 @@ process:
       5: "Print"
       teaser: "Teaser"
       full: "Full"
-  targetEntityType: 'constants/targetEntityType'
+  targetEntityType: 'constants/entity_type'
   status: 'constants/status'
 destination:
   plugin: entity:entity_view_mode

core/modules/node/src/Plugin/migrate/source/d6/ViewMode.php

@@ -71,6 +71,7 @@ public function getIds() {
   public function calculateDependencies() {
     $this->dependencies = parent::calculateDependencies();
     if (isset($this->configuration['constants']['targetEntityType'])) {
+      @trigger_error('The constant targetEntityType is deprecated in drupal:9.2.0 and is removed in drupal:10.0.0. Use entity_type instead. See https://www.drupal.org/node/3208135', E_USER_DEPRECATED);
       $this->addDependency('module', $this->entityTypeManager->getDefinition($this->configuration['constants']['targetEntityType'])->getProvider());
     }
     return $this->dependencies;