runtime(tutor): update the tutor files and re-number the chapters

closes: #16110

Signed-off-by: RestorerZ <restorer@mail2k.ru>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/doc/vimtutor-it.1 b/runtime/doc/vimtutor-it.1
index 28d921b..47952c7 100644
--- a/runtime/doc/vimtutor-it.1
+++ b/runtime/doc/vimtutor-it.1
@@ -76,7 +76,7 @@
 .fi
 .SH FILE
 .TP 15
-/usr/local/lib/vim/vim??/tutor/tutor[.lingua]
+/usr/local/lib/vim/vim??/tutor/tutor1[.lingua]
 I file di testo per il capitolo uno di
 .B Vimtutor
 .