docs: Fix incorrect example for regex.template_match
docs: Fix incorrect example for regex.template_match

regex.template_match both per the code as well as the documentation
takes 4 string arguments and returns one boolean. The example had a 5th
argument that looked to be an out value. Remove the extra argument and
clean up the text.

Signed-off-by: Brian Atkinson <760e7dab2836853c63805033e514668301fa9c47@atkinson.mn>

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