Document that setting will be rounded to one of the settings options.

src/config/default-app-config.ts

@@ -207,6 +207,8 @@ export class DefaultAppConfig implements AppConfig {
     // The absolute lowest year to display in the dropdown (only used when no lowest date can be found for all items)
     defaultLowerLimit: 1900,
     // The number of entries in a paginated browse results list.
+    // Rounded to the nearest size in the list of selectable sizes on the
+    // settings menu.  See pageSizeOptions in 'pagination-component-options.model.ts'.
     pageSize: 20
   };