address warnings in Routing manager

[kianzarrin]

Note: the code is functionally the same. just resolved some warnings and renamed some variables. its easier to follow the commits for individual changes.

• in routing manager I can understand why we refer to next/prev segment as such but I don't understand why we call the "common node" the "next node". I decided to just call it node to avoid confusion.
• removed duplicated variables and added doc

also fixed these warnings:

• commented out code should not exist (if necessary then create issue | if not necessary then delete).
• avoid using obsolete code.
• observe order of members a little bit but also turned off the warning because we usually don't observe it.
• use new () to instantiate
• use inline struct initializer.
• turned off some warnings that I deemed unnecessary because we usually don't follow it anyway.

I think we should not have warning rules that are usually broken because too many warnings means that we will ignore them. If we do have a warning it should be consistent with code cleanup tool.

I made this a draft because I had some questions.

[kianzarrin]

sorry @aubergine10 I did a few more renames/docs

[originalfoo]

sorry @aubergine10 I did a few more renames/docs

Yeah, I've been following the commits - still looks good. Definite improvement in legibility. 👍