Fix link to Code of Conduct in CONTRIBUTING.md

What does this MR do and why?

• fix link to Code of Conduct
• condense some of the subheadings that were all linking to the same page to make it easier to read
• change View the new documentation to find the latest information into View the documentation to find the latest information since the new should no longer be necessary
• change This documentation has been moved into View the documentation to find the latest information since we no longer need to inform that it's been moved, just where it is
• fix some vale errors

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.