ComposeMenu [nfc]: Fix name of insertAttachment prop to be plural

This function is designed to insert multiple attachments.

Author: chrisbobbe

src/compose/ComposeBox.js

@@ -319,7 +319,7 @@ const ComposeBox: React$AbstractComponent<Props, ImperativeHandle> = forwardRef(
   );
 
   const [numUploading, setNumUploading] = useState<number>(0);
-  const insertAttachment = useCallback(
+  const insertAttachments = useCallback(
     async (attachments: $ReadOnlyArray<DocumentPickerResponse>) => {
       setNumUploading(n => n + 1);
       try {
@@ -744,7 +744,7 @@ const ComposeBox: React$AbstractComponent<Props, ImperativeHandle> = forwardRef(
           />
           <ComposeMenu
             destinationNarrow={destinationNarrow}
-            insertAttachment={insertAttachment}
+            insertAttachments={insertAttachments}
             insertVideoCallLink={
               videoChatProvider !== null ? () => insertVideoCallLink(videoChatProvider) : null
             }

src/compose/ComposeMenu.js

@@ -22,7 +22,7 @@ import type { SpecificIconType } from '../common/Icons';
 
 type Props = $ReadOnly<{|
   destinationNarrow: Narrow,
-  insertAttachment: ($ReadOnlyArray<DocumentPickerResponse>) => Promise<void>,
+  insertAttachments: ($ReadOnlyArray<DocumentPickerResponse>) => Promise<void>,
   insertVideoCallLink: (() => void) | null,
 |}>;
 
@@ -95,7 +95,7 @@ function MenuButton(props: MenuButtonProps) {
 }
 
 export default function ComposeMenu(props: Props): Node {
-  const { destinationNarrow, insertAttachment, insertVideoCallLink } = props;
+  const { destinationNarrow, insertAttachments, insertVideoCallLink } = props;
 
   const dispatch = useDispatch();
   const _ = useContext(TranslationContext);
@@ -221,8 +221,8 @@ export default function ComposeMenu(props: Props): Node {
       return;
     }
 
-    insertAttachment(response);
-  }, [_, insertAttachment]);
+    insertAttachments(response);
+  }, [_, insertAttachments]);
 
   const styles = useMemo(
     () =>