Login: Fix typo in help message

Reported by zuMi, while contributing to the Italian translations. Thanks!

Change-Id: I15e8fc17390188c6d0051384d047ebe06d19a2bc
Reviewed-on: https://review.haiku-os.org/c/haiku/+/5677
Tested-by: Commit checker robot <[email protected]>
Reviewed-by: Jérôme Duval <[email protected]>

src/apps/login/LoginApp.cpp

@@ -132,7 +132,7 @@ LoginApp::ArgvReceived(int32 argc, char **argv)
 			puts(B_TRANSLATE("Login application for Haiku\nUsage:"));
 			printf("%s [--nonmodal] [--edit]\n", argv[0]);
 			puts(B_TRANSLATE("--nonmodal	Do not make the window modal"));
-			puts(B_TRANSLATE("--edit	Launch in shelf editting mode to "
+			puts(B_TRANSLATE("--edit	Launch in shelf editing mode to "
 				"allow customizing the desktop."));
 			// just return to the shell
 			exit((arg == "--help") ? 0 : 1);