Clarity.

Existing Wording:

In addition to their use as part of valueset definitions, codesystem definitions can be referenced directly within an expression, just like valueset definitions. See the Valuesets section for an example codesystems declaration.

Proposed Wording:

In addition to their use as part of valueset definitions, codesystem definitions can be referenced directly within an expression, just like valueset definitions. See the Valuesets section for an example of a codesystems declaration.