patch 9.0.1722: wrong error messages when passing wrong types to count()

patch 9.0.1722: wrong error messages when passing wrong types to count()

Problem: wrong error messages when passing wrong types to count()
Solution: fix it

This fixes two problems:
1. When passing wrong type to {ic} argument of count(), two error
   messages are given, the second of which is misleading.
2. When passing wrong type to {comp} argument of count(), the error
   message doesn't mention that {comp} may be a String.

closes: #12825

Signed-off-by: Christian Brabandt <cb@256bit.org>
Co-authored-by: zeertzjq <zeertzjq@outlook.com>