Duplicated links and simplification of sentences

[IshitaTakeshi]

1. Duplicated links

I'm seeing the raw text of the contribution guideline and it has two consecutive #contribution-workflows. Is this a mistake?

First, conform to the [Code of conduct](#contribution-workflows) section for the general manners in contributions.

See the [Contribution workflows](#contribution-workflows) section for the workflows.  

2. Sentence simplification

It also says

It is recommended to read the Contributing pages in ROS 2 Docs as well because Autoware's guidelines generally depend on them.

but it implicitly asks contributors to know all the ROS2 contribution manners beforehand. We should decrease contributors' stress and burden so I think it's better to say

We follow the ROS2 contribution guide unless otherwise stated.

Then contributors can refer to the ROS2 contribution guide when they cannot find a proper guideline in our documentation.

3. Link to the OSS guide

In the last of the section, it says

For general information about OSS contributions, Open Source Guides by GitHub is a good resource.

Is this necessary? I think most of the contributors already know the basic instructions or they can search by themselves, and also this documentation contains general information about OSS so not very much related to this documentation.