chore: remove 'upstream' references — describe behavior directly

Author: johanrd

lib/rules/template-no-passed-in-event-handlers.js

@@ -1,8 +1,7 @@
 // Ember event handler names that map to Ember's classic event system.
-// Matches upstream ember-template-lint's no-passed-in-event-handlers list exactly.
 // Note: mouseMove, mouseEnter, and mouseLeave are intentionally excluded —
-// upstream does not include them, as they are native DOM events that do not
-// have corresponding Ember classic-event aliases on components.
+// they are native DOM events that do not have corresponding Ember
+// classic-event aliases on components.
 const EMBER_EVENTS = new Set([
   'touchStart',
   'touchMove',

tests/lib/rules/template-no-passed-in-event-handlers.js

@@ -40,7 +40,7 @@ ruleTester.run('template-no-passed-in-event-handlers', rule, {
     '<template><my-button @click={{this.handleClick}} /></template>',
     '<template><custom-el @submit={{this.handleSubmit}} /></template>',
 
-    // mouseMove/mouseEnter/mouseLeave are NOT in upstream's event list
+    // mouseMove/mouseEnter/mouseLeave are not Ember classic-event aliases
     '<template><Foo @mouseMove={{this.handleMove}} /></template>',
     '<template><Foo @mouseEnter={{this.handleEnter}} /></template>',
     '<template><Foo @mouseLeave={{this.handleLeave}} /></template>',