Add substring support for binary (#1608)

* add substring for binary
fix some test for string array

Signed-off-by: remzi <13716567376yh@gmail.com>

* fix another bug in test

Signed-off-by: remzi <13716567376yh@gmail.com>

* update doc

Signed-off-by: remzi <13716567376yh@gmail.com>

* add with_nulls tests

Signed-off-by: remzi <13716567376yh@gmail.com>

* add without_nulls tests

Signed-off-by: remzi <13716567376yh@gmail.com>

* fix clippy

Signed-off-by: remzi <13716567376yh@gmail.com>