Remove parameter @dir on content component (#1036)

* Remove option to pass parameter `@dir` to BasicDropdownContent

* Add change in docs

Author: mkszepp

docs/app/templates/public-pages/docs/migrate-8-0-to-9-0.gts

@@ -52,6 +52,14 @@ import { LinkTo } from '@ember/routing';
         Note: This option was never documented.
       </p>
     </li>
+    <li>
+      <p>
+        Passing
+        <code>@dir</code>
+        to the content component has been removed. Please pass this parameter as
+        a regular HTML attribute instead.
+      </p>
+    </li>
     <li>
       <p>
         If you are using

ember-basic-dropdown/src/components/basic-dropdown-content.gts

@@ -45,7 +45,6 @@ export interface BasicDropdownContentSignature {
     otherStyles?: Record<string, string | number | undefined>;
     hPosition?: HorizontalPosition | null;
     vPosition?: VerticalPosition | null;
-    dir?: string;
     defaultClass?: string;
     overlay?: boolean;
     htmlTag?: keyof HTMLElementTagNameMap;
@@ -554,7 +553,6 @@ export default class BasicDropdownContent extends Component<BasicDropdownContent
                   ' ember-basic-dropdown-content--in-place'
                 }}
                 {{@defaultClass}}"
-              dir={{@dir}}
               ...attributes
               {{style @otherStyles this.positionStyles}}
               {{this.respondToEvents}}
@@ -586,7 +584,6 @@ export default class BasicDropdownContent extends Component<BasicDropdownContent
                     ' ember-basic-dropdown-content--in-place'
                   }}
                   {{@defaultClass}}"
-                dir={{@dir}}
                 ...attributes
                 {{style @otherStyles this.positionStyles}}
                 {{this.respondToEvents}}