patch 8.2.2160: various typos

Problem:    Various typos.
Solution:   Fix spelling mistakes. (closes #7494)
diff --git a/src/gui_haiku.cc b/src/gui_haiku.cc
index c929409..a1c7e3e 100644
--- a/src/gui_haiku.cc
+++ b/src/gui_haiku.cc
@@ -3411,7 +3411,7 @@
 	thread_id tid = gui.vimWindow->Thread();
 	gui.vimWindow->Lock();
 	gui.vimWindow->Quit();
-	// Wait until it is truely gone
+	// Wait until it is truly gone
 	int32 exitcode;
 	wait_for_thread(tid, &exitcode);
     }