fix(#1349): Change label of Proposal Discussion nav item

[MSzalowski]

List of changes

• Change label of Proposal Discussion nav item

Checklist

• related issue
• My changes generate no new warnings
• My code follows the style guidelines of this project
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the changelog
• I have added tests that prove my fix is effective or that my feature works