Fix some bullet points in 'contribute.md' file as well as some improvments to the graph

[og-mrk]

Type of Change

• Documentation update

Screenshots

Before

After

Checklist

• My code adheres to the coding and style guidelines of the project.
• I have performed a self-review of my own code.
• I have commented my code, particularly in hard-to-understand areas.
• I have made corresponding changes to the documentation.
• My changes generate no errors/warnings/merge conflicts.