Clarify merge request approval section description

Problem to solve

The generic message for merge request approvals does not adequately describe what the section entails. Link separation of duties to docs.

Proposal

Update the text to clarify each section in its respective area and maintain consistency.

Admin Area

Merge request (MR) approvals

We do not use "MR" anymore

Configure approvals by authors and committers on all projects.
Enforce separation of duties for all projects. Learn more.

I'm trying to communicate the intent of the feature, and make more consistent message across the various layers

Group

Define approval settings. Learn more.
Enforce separation of duties for all projects. Learn more.

Keep it consistent with the Admin Area.

Project

Merge request (MR) approvals

Define approval settings. Learn more.
Define approval rules and settings to ensure separation of duties for new merge requests. Learn more.

Mere request approvals only impact future merge requests. They do not retroactively update existing ones, which I think needs to be communicated.