fix doc strings

Signed-off-by: Miaofei <miaofei@amazon.com>

rclpy/rclpy/node.py

@@ -1665,17 +1665,18 @@ def get_publishers_info_by_topic(
         The returned parameter is a list of dictionaries, where each dictionary will
         contain the node name, node namespace, topic type, participant's GID and its QoS profile.
 
-        'topic_name' may be a relative, private or fully qualified topic name.
-        A relative or private topic will be expanded using this node's namespace and name, if
-        the 'no_mangle' param is set to false.
+        When the `no_mangle` parameter is `true`, the provided `topic_name` should be a valid topic
+        name for the middleware (useful when combining ROS with native middleware (e.g. DDS) apps).
+        When the `no_mangle` parameter is `false`, the provided `topic_name` should follow
+        ROS topic name conventions.
 
-        The queried topic name is not remapped.
-
-        'no_mangle' defaults to false.
+        `topic_name` may be a relative, private, or fully qualified topic name.
+        A relative or private topic will be expanded using this node's namespace and name.
+        The queried `topic_name` is not remapped.
 
         :param topic_name: the topic_name on which to find the publishers.
-        :param no_mangle: if false, the given topic name will be expanded
-                          to its fully qualified name.
+        :param no_mangle: no_mangle if `true`, `topic_name` needs to be a valid middleware topic
+                          name, otherwise it should be a valid ROS topic name. Defaults to `false`.
         :return: a list of dictionaries representing all the publishers on this topic.
         """
         return self._get_info_by_topic(
@@ -1691,17 +1692,18 @@ def get_subscriptions_info_by_topic(
         The returned parameter is a list of dictionaries, where each dictionary will contain
         the node name, node namespace, topic type, participant's GID and its QoS profile.
 
-        'topic_name' may be a relative, private or fully qualified topic name.
-        A relative or private topic will be expanded using this node's namespace and name, if
-        the 'no_mangle' param is set to false.
-
-        The queried topic name is not remapped.
+        When the `no_mangle` parameter is `true`, the provided `topic_name` should be a valid topic
+        name for the middleware (useful when combining ROS with native middleware (e.g. DDS) apps).
+        When the `no_mangle` parameter is `false`, the provided `topic_name` should follow
+        ROS topic name conventions.
 
-        'no_mangle' defaults to false.
+        `topic_name` may be a relative, private, or fully qualified topic name.
+        A relative or private topic will be expanded using this node's namespace and name.
+        The queried `topic_name` is not remapped.
 
         :param topic_name: the topic_name on which to find the subscriptions.
-        :param no_mangle: if false, the given topic name will be expanded
-                          to its fully qualified name.
+        :param no_mangle: no_mangle if `true`, `topic_name` needs to be a valid middleware topic
+                          name, otherwise it should be a valid ROS topic name. Defaults to `false`.
         :return: a list of dictionaries representing all the subscriptions on this topic.
         """
         return self._get_info_by_topic(

rclpy/src/rclpy/_rclpy.c

@@ -917,8 +917,8 @@ _get_info_by_topic(
  *
  * \param[in] pynode Capsule pointing to the node to get the namespace from.
  * \param[in] topic_name the topic name to get the publishers for.
- * \param[in] no_mangle if true the given topic name will be
- *            expanded to its fully qualified name.
+ * \param[in] no_mangle if `true`, `topic_name` needs to be a valid middleware topic name,
+ *            otherwise it should be a valid ROS topic name.
  * \return list of publishers
  */
 static PyObject *
@@ -934,8 +934,8 @@ rclpy_get_publishers_info_by_topic(PyObject * Py_UNUSED(self), PyObject * args)
  *
  * \param[in] pynode Capsule pointing to the node to get the namespace from.
  * \param[in] topic_name the topic name to get the subscriptions for.
- * \param[in] no_mangle if true the given topic name will be
- *            expanded to its fully qualified name.
+ * \param[in] no_mangle if `true`, `topic_name` needs to be a valid middleware topic name,
+ *            otherwise it should be a valid ROS topic name.
  * \return list of subscriptions.
  */
 static PyObject *