Updates Windows installation from source

[mabelzhang]

A few corrections of the documentation for compiling ROS 2 Foxy from source on Windows.

I’ve just used these instructions to do my very first install of ROS on Windows (wow it worked, mostly. Shocking), in default mode first and then Debug mode. There are a few places that can be improved so that I can remove the “mostly” in the previous sentence and save someone a few hours, especially in Debug mode :) This PR does that.

Explanations for the changes I made:

• The most important thing is this flag to colcon in Debug mode:

  --cmake-args -DCMAKE_BUILD_TYPE=Debug
  

  Without this, python_d colcon behaves as if I am running python.exe as opposed to python_d.exe and cannot find the numpy that is specifically reinstalled for the debug mode. If I run python_d manually, it runs the erroring line importing numpy just fine. If I run python, then I can reproduce the error colcon gives me.

• Removed RQt instructions in the source install page. It's a redundancy of the dependency page in the binary installation, which the source installation points to.

• Removed instructions for setting environment variable PATH in RQt section in binary dependencies page. It's redundant (and has several typos anyway). It's already detailed in the OpenSSL section earlier, and then simply omitted in the Install dependencies section assuming you've read the OpenSSL section, and then in the RQt section, it for some reason goes over a longer way to do it from the Control Panel, which is odd and reads disconnected from the previous instructions.

• The rest are just typos. I also felt using >>> to differentiate between the Python prompt and the Windows prompt > was helpful for the reader to see they're supposed to be in a Python shell after running python_d.

Cookbook?

Kind of related, should we mention the new Windows Chef Cookbook anywhere in the Windows tutorials? I think it might save someone even more hours https://discourse.ros.org/t/introducing-the-ros-2-windows-chef-cookbook-and-ci-integration/15815

I haven't tried it to know how well it works. I mostly mention it because I’ve heard people in the community who felt discouraged from developing with ROS 2 on Windows, because there are… I count 21 dependencies (not including 3 more in Debug mode) that I had to install manually, and that does not include ROS 2 itself.

Signed-off-by: Mabel Zhang [email protected]

[clalancette]

One minor thing to change to avoid a conflict, otherwise looks like good clarification to me.

[clalancette]

@mabelzhang Can you rebase this now that #851 went in? Thanks.