narrow [nfc]: Fix a comment reference to getNarrowForReply.

Which was recently renamed from getNarrowFromMessage.

src/utils/narrow.js

@@ -71,7 +71,7 @@ const pmNarrowByString = (emails: string): Narrow => [
 //      the webapp, where the URL that appears in the location bar for a
 //      group PM conversation excludes self -- so it's unusable if you try
 //      to give someone else in it a link to a particular message, say.
-//  * OK, unsorted: getNarrowFromMessage
+//  * OK, unsorted: getNarrowForReply
 //  * Good: getNarrowFromNotificationData: filters, and starts from
 //      notification's pm_users, which is sorted.
 //  * Good: messageHeaderAsHtml: comes from pmKeyRecipientsFromMessage,