docs(api): updated projects API docs

It was not covering some recently introduced parameters.

See #19867

Author: nijel

docs/api.rst

@@ -941,6 +941,7 @@ Projects
                             assigned to a workspace
     :>json string instructions: :ref:`project-instructions`
     :>json string language_aliases: :ref:`project-language_aliases`
+    :>json string license: :ref:`project-license`
     :>json string announcements_url: URL to announcements; see :http:get:`/api/projects/(string:project)/announcements/`
 
     **Example JSON data:**
@@ -961,6 +962,22 @@ Projects
 
     Edit a project by a :http:method:`PATCH` request.
 
+    The ``project`` value is the project slug. To avoid using a wrong
+    identifier, use the project ``url`` returned by :http:get:`/api/projects/`
+    or :http:get:`/api/projects/(string:project)/`.
+
+    The request body accepts project fields such as ``instructions`` and
+    ``license``.
+
+    **Example JSON data:**
+
+    .. code-block:: json
+
+        {
+            "instructions": "Translate consistently.",
+            "license": "MIT"
+        }
+
     Changing ``workspace`` moves the project. Moving a project requires
     permission to edit the project and the :guilabel:`Edit workspace settings`
     permission for the source and target workspace. The target workspace also
@@ -970,6 +987,10 @@ Projects
 
     :param project: Project URL slug
     :type project: string
+    :param instructions: :ref:`project-instructions`
+    :type instructions: string
+    :param license: :ref:`project-license`
+    :type license: string
     :param workspace: Optional workspace UUID, or ``null`` to move the project
                        out of a workspace
     :type workspace: string
@@ -985,6 +1006,10 @@ Projects
 
     :param project: Project URL slug
     :type project: string
+    :param instructions: :ref:`project-instructions`
+    :type instructions: string
+    :param license: :ref:`project-license`
+    :type license: string
 
 .. http:delete:: /api/projects/(string:project)/