Document search modal configuration and subproject filtering (#12936)

Follow-up to #12843, which moved project search configuration into its
own dedicated settings page. Updates the existing "Configurable" bullet
in the server-side search docs and the "Search" section in the
subprojects docs to point readers at `Settings > Search`.

Closes #11533.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

---------

Co-authored-by: Claude <noreply@anthropic.com>

Author: ericholscher

docs/user/server-side-search/index.rst

@@ -47,6 +47,9 @@ Special query syntax for more specific results
 Configurable
    Tweak search results according to your needs using a
    :ref:`configuration file <config-file/v2:search>`.
+   You can also enable or disable the search modal,
+   and toggle the subprojects filter shown inside it,
+   from your project's :guilabel:`Settings`, in the left bar, under :guilabel:`Search`.
 
 Ready to use
    We override the default search engine of your Sphinx project with ours
@@ -82,6 +85,21 @@ It also saves recent searches, for future reference.
 
 Try it by pressing :guilabel:`/` (forward slash) and typing.
 
+Configuring search
+------------------
+
+You can configure search options for your project from the :term:`dashboard`:
+
+#. Go to the :term:`dashboard`.
+#. Click on a project name.
+#. Go to :guilabel:`Settings`.
+#. In the left bar, go to :guilabel:`Search`.
+
+From there you can toggle :guilabel:`Enable search modal`,
+which controls whether the Read the Docs search modal is shown in your documentation,
+and :guilabel:`Show subprojects filter in search modal`,
+which controls whether readers can filter search results by :doc:`subproject </subprojects>`.
+
 How main content is detected
 ----------------------------
 

docs/user/subprojects.rst

@@ -94,10 +94,15 @@ they are presented with a flyout menu matching the subproject's versions and :do
 Search
 ------
 
-Search on the parent project will include results from its subprojects.
+Search on the parent project will include results from its subprojects,
+and readers can filter results by subproject from the search modal.
 If you search on the ``v1`` version of the parent project,
 results from the ``v1`` version of its subprojects will be included,
 or from the default version for subprojects that don't have a ``v1`` version.
 
 This is currently the only way to share search results between projects,
 we do not yet support sharing search results between sibling subprojects or arbitrary projects.
+
+The subprojects filter in the search modal can be turned off from the parent project's
+:guilabel:`Settings`, in the left bar, under :guilabel:`Search`,
+by disabling :guilabel:`Show subprojects filter in search modal`.