Update count function doc to mention strings (#1126)
Update count function doc to mention strings (#1126)

* Update count function doc to mention strings

Updates the doc for the built-in function count to mention strings.

Fixes #1122

Signed-off-by: Fraser Cobb <90cc25f67c02595ba10aa8b094ecd7f09150363b@gmail.com>

open-policy-agent/opa,open-policy-agent/opa,tsandall/opa,tsandall/opa,tsandall/opa,open-policy-agent/opa,open-policy-agent/opa,tsandall/opa,tsandall/opa,open-policy-agent/opa,tsandall/opa,open-policy-agent/opa