docs(localization_landmarks): add localization reflector subtype (#44)

doc: add localization reflector subtype

Signed-off-by: Motsu-san <masahiro.sakamoto@tier4.jp>

Author: Motsu-san

autoware_lanelet2_extension/docs/lanelet2_format_extension.md

@@ -300,7 +300,9 @@ Landmark Specifications:
   - The y-axis must be parallel to the vector extending from the second vertex to the third vertex.
 - **Required Attributes**:
   - Specify pose_marker for type `<tag k="type" v="pose_marker"/>`
-  - Specify the type of the landmark for subtype `<tag k="subtype" v="apriltag_16h5"/>`
+  - Specify the type of the landmark for subtype
+    - [AR-Tag](https://autowarefoundation.github.io/autoware.universe/main/localization/autoware_landmark_based_localizer/autoware_ar_tag_based_localizer/): `<tag k="subtype" v="apriltag_16h5"/>`
+    - [Reflector](https://autowarefoundation.github.io/autoware.universe/main/localization/autoware_landmark_based_localizer/autoware_lidar_marker_localizer/): `<tag k="subtype" v="reflector"/>`
   - Specify the ID of the landmark for marker_id `<tag k="marker_id" v="0"/>`
     - ID can be assigned arbitrarily as a string, but the same ID must be assigned for the same marker type
     - For example, apiltag_16h5 has 30 different IDs from 0 to 29. If multiple tags of the same type are to be placed in one environment, they should be assigned the same ID.