i18n: fix minor issues in English strings

Thanks for the reports via Pootle (i18n.haiku-os.org)

src/add-ons/mail_daemon/inbound_filters/notifier/NotifierFilter.cpp

@@ -78,7 +78,7 @@ NotifyFilter::MailboxSynchronized(status_t status)
 
 	if ((fStrategy & NOTIFY_ALERT) != 0) {
 		BStringFormat format(B_TRANSLATE(
-			"You have {0, plural, one{One new message} other{# new messages}} "
+			"You have {0, plural, one{one new message} other{# new messages}} "
 			"for %account."));
 
 		BString text;

src/apps/haikudepot/ui/MainWindow.cpp

@@ -957,7 +957,7 @@ MainWindow::_BulkLoadProcessCoordinatorFinished(
 			B_TRANSLATE("Package Update Error"),
 			B_TRANSLATE("While updating package data, a problem has arisen "
 				"that may cause data to be outdated or missing from the "
-				"application's display.  Additional details regarding this "
+				"application's display. Additional details regarding this "
 				"problem may be able to be obtained from the application "
 				"logs."));
 	}