patch 9.1.1421: tests: need a test for the new-style tutor.tutor

Problem:  tests: need a test for the new-style tutor.tutor, patch
          9.1.1384 broke the expected positions for the signs
Solution: Update all number keys in tutor.tutor.json to match the
          correct line numbers in tutor.tutor, replace tabs by spaces,
          add a screen-dump test to verify it does not regress
          (Pham Bình An)

closes: #17416

Signed-off-by: Phạm Bình An <phambinhanctb2004@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/version.c b/src/version.c
index 2316def..7530124 100644
--- a/src/version.c
+++ b/src/version.c
@@ -710,6 +710,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1421,
+/**/
     1420,
 /**/
     1419,