patch 9.0.1973: Clean up cmdline option completion code

Problem:  Clean up cmdline option completion code
Solution: Fix various minor problems

- Fix manual array size calculations to just use `ARRAY_LENGTH()`.
- Fix unintentional typo in comments due to copy-paste error.
- Fix assert_equal() usages to pass the expected value to first
  parameter instead of 2nd one to avoid confusion.
- Fix signed vs unsigned warnings
- Correct misplaced comments about set_op_T and set_prefix_T
  and fix a typo in another comment

closes: #13249
closes: #13237

Signed-off-by: Christian Brabandt <cb@256bit.org>
Co-authored-by: Yee Cheng Chin <ychin.git@gmail.com>
Co-authored-by: zeertzjq <zeertzjq@outlook.com>
diff --git a/src/move.c b/src/move.c
index 9c025d4..ba1eadb 100644
--- a/src/move.c
+++ b/src/move.c
@@ -3587,7 +3587,7 @@
     FOR_ALL_WINDOWS(curwin)
     {
 	curbuf = curwin->w_buffer;
-	// skip original window  and windows with 'noscrollbind'
+	// skip original window and windows with 'nocursorbind'
 	if (curwin != old_curwin && curwin->w_p_crb)
 	{
 # ifdef FEAT_DIFF