feat(#2080): add section for default parameters

docs/central-submissions.rst

@@ -75,6 +75,17 @@ Once a Link is created, it will appear in the table, along with a web address yo
 
 You cannot yet edit any of the details of a Public Link.
 
+.. _central-submissions-link-default-parameters:
+
+Default Parameters
+^^^^^^^^^^^^^^^^^^
+
+Parameters use the format :code:`d[{field}]={value}`, where ``field`` identifies the form field you want to set and ``value`` is the text to put in it. For example, :code:`d[name]=odk` sets the ``name`` field to ``odk``. For a field inside groups or repeats, include the names of the groups or repeats in the field identifier, separated by slashes. For example: :code:`d[person/name]=Maria`.
+
+To set multiple fields, separate parameters with an ampersand (``&``), for example: :code:`?d[name]=odk&d[engine]=webforms`.
+
+Note that the parameters must be URL encoded to be parsed correctly.
+
 .. _central-submissions-link-revoke:
 
 Revoking a Link

docs/web-forms-intro.rst

@@ -32,7 +32,6 @@ We've extensively tested ODK Web Forms and consider it ready for production use
 For users who have been using web forms in Central prior to v2026.2.0, here is functionality in Enketo that's coming to Web Forms, in rough order of priority:
 
 * One question per page
-* Query parameter defaults
 * Jump to first error
 * Last-saved
 * Satellite basemaps