Typo in melodic build doc: "从源码安装ROS 2 | Building ROS 2 from source"

https://github.com/MiRoboticsLab/cyberdog_ros2/wiki/从源码安装ROS-2-%7C-Building-ROS-2-from-source#English

mi@lubuntu:~/cyberdog_ros2$ git diff
diff --git a/tools/ros2_fork/extend.repos b/tools/ros2_fork/extend.repos
index 6ae5252..d7828e3 100644
--- a/tools/ros2_fork/extend.repos
+++ b/tools/ros2_fork/extend.repos
@@ -23,7 +23,7 @@ repositories:
     type: git
     url: https://github.com/ros-planning/navigation_msgs.git
     version: 2.1.0
-   ros-visualization/interactive_markers:
+  ros-visualization/interactive_markers:
     type: git
     url: https://github.com/ros-visualization/interactive_markers.git
     version: 2.2.0

Will cause the following error when following the instructions

mi@lubuntu:~/ros_src$ vcs import src < extend.repos
Input data is not valid yaml format: while parsing a block mapping
  in "<stdin>", line 2, column 3
expected <block end>, but found '<block mapping start>'
  in "<stdin>", line 26, column 4

Open the linked wiki page and inspect tools/ros2_fork/extend.repos around the ros-visualization/interactive_markers entry. Run vcs import with the manifest to reproduce the YAML error, then verify that the documented build step completes without the parsing failure.