Tweak ros2_overview tutorial.

[caguero]

🦟 Bug fix

This patch fixes one typo and the figure (the parameter values were wrong). Thanks @azeey for catching it.

Summary

Checklist

• Signed all commits for DCO
• Added tests
• Updated documentation (as needed)
• Updated migration guide (as needed)
• Consider updating Python bindings (if the library has them)
• codecheck passed (See contributing)
• All tests passed (See test coverage)
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[azeey]

Thanks @caguero. One other thing I noticed on the image on the right is that it's not clear that Gazebo and the bridge are running in the same container and nav2 is running outside of that container. Could you add something to the graphics to group Gazebo and the bridge together?

[caguero]

Thanks @caguero. One other thing I noticed on the image on the right is that it's not clear that Gazebo and the bridge are running in the same container and nav2 is running outside of that container. Could you add something to the graphics to group Gazebo and the bridge together?

The intent of the right image is to show that the three nodes can be running within the same process. However, we're not starting the container ourselves..