patch 8.2.2829: some comments are not correct or clear

Problem:    Some comments are not correct or clear.
Solution:   Adjust the comments.  Add test for cursor position.
diff --git a/src/testdir/test_substitute.vim b/src/testdir/test_substitute.vim
index f38eb55..4c99f81 100644
--- a/src/testdir/test_substitute.vim
+++ b/src/testdir/test_substitute.vim
@@ -926,4 +926,13 @@
   close!
 endfunc
 
+func Test_substitute_skipped_range()
+  new
+  if 0
+    /1/5/2/2/\n
+  endif
+  call assert_equal([0, 1, 1, 0, 1], getcurpos())
+  bwipe!
+endfunc
+
 " vim: shiftwidth=2 sts=2 expandtab