I'm not following your train of thought here. Since null == null in json-land there isn't a need for or concept of "is distinct from". We tend to not expend space on pointing out things that don't exist.
But you said previously in this document about IS DISTINCT, so it's related to NULL. I thought it would be better to mention that here, for JSON PATH, that way doesn't exist.
"JSON null value is considered equal to other JSON null values, so here we don't have the IS DISTINCT operator"
I added this to "Overview"
<para> Throughout this section the discussion of null values will be limited to the SQL language unless otherwise noted. The JSON-related data types, and the non-SQL procedural languages, have their own behaviors documented in their respective areas. </para>
And added this to "Distinctness..."
<para> On the other hand, the SQL specification is largely alone in taking this approach to comparing values to the null value. Specifically, when working within the JSON data types the use of equals produces true or false and so the concept of distinctness is neither present nor required. Please consult the documentation for the non-SQL procedural language of choice to learn about its behavior. </para>
I'm OK with adding more cross-references (links or just brief comparative verbiage like the above) to non-SQL null value treatment but this document, for this patch, is going to focus solely on SQL NULL.
