Description of Equivalent in Comparison Operators is inconsistent with Reference

[brynrhodes]

The discussion at the end of the Comparison Operators section is inconsistent with the description of Equivalent functionality in the Logical Specification and CQL Reference. Specifically, it says: "The equivalent operator is the same as equality, except that it returns true if both of the arguments are null, and false if one argument is null and the other is not:" But it should note that equivalence has looser semantics than strict equality for many types (e.g. Strings, Codes, Concepts, and Quantities).