docs(filter): the applied clause carries SAS temporal literals

The clause shown above the grid is the resolved WHERE clause, so a date,
datetime or time filter reads as a SAS literal rather than the internal day or
second count.  Note it on the filter page and on the MPE_FILTERSOURCE RAW_VALUE
column, which is where the value is stored.

docs/filter.md

@@ -9,6 +9,8 @@ og_image:  https://docs.datacontroller.io/img/filter_dynamic_on.png
 
 Data Controller for SAS® enables you to create complex table filters. The "dynamic" setting enables the dropdown values to be pre-filtered by previous filter clauses.  Filtered views are shareable!  They are also used when [embedded in VA.](/embed-va)
 
+The clause shown above the grid is the resolved WHERE clause that was applied, so it uses SAS syntax - a date, datetime or time filter reads as a SAS literal, eg `SOME_DATE = '20APR2042'd`, rather than the internal day or second count.
+
 ## Shared Filters
 
 When filters are submitted, the query is stored, and a unique URL is generated.  This means you can share the link to a filtered view of a table!  This can be used for VIEW, for EDIT and also for downloading data.