Issue #2288185 by typhonius: Fixed Typos around the codebase for OPML.

core/modules/aggregator/aggregator.routing.yml

@@ -35,7 +35,7 @@ aggregator.opml_add:
   path: '/admin/config/services/aggregator/add/opml'
   defaults:
     _form: '\Drupal\aggregator\Form\OpmlFeedAdd'
-    _title: 'Import OMPL'
+    _title: 'Import OPML'
   requirements:
     _permission: 'administer news feeds'
 

core/modules/views_ui/src/Tests/DisplayFeedTest.php

@@ -40,7 +40,7 @@ class DisplayFeedTest extends UITestBase {
    * Tests feed display admin UI.
    */
   public function testFeedUI() {
-    // Test both RSS and OMPL feeds.
+    // Test both RSS and OPML feeds.
     foreach (self::$testViews as $view_name) {
       $this->checkFeedViewUi($view_name);
     }