Improve CI/CD settings documentation (pt.3)

What does this MR do and why?

This MR continues the improvements to the CI/CD settings documentation in the Admin area by applying a task-oriented approach to the pipeline-related settings.

These changes make the documentation more user-friendly by:

• Making it easier for users to quickly find the specific tasks they want to accomplish.
• Providing clear, consistent instructions that focus on what users can do.
• Ensuring consistency in terminology and structure throughout the document.

Changes

• Converted all section headings to follow a task-oriented pattern with action verbs (Set, Limit, Manage, etc.).
• Rewrote section introductions to use direct, action-oriented language.
• Standardized procedural instructions with clear "To..." introductions.
• Improved readability with consistent formatting and structure.
• Updated related anchor links.

Sections updated

This MR focuses on the following pipeline-related sections under "Continuous Integration and Deployment":

• In the Pipelines subsection:
  • Protect CI/CD variables by default
  • Set maximum includes (renamed from "Maximum includes")
  • Limit downstream pipeline trigger rate (renamed from "Maximum downstream pipeline trigger rate")
  • Specify a default CI/CD configuration file (renamed from "Default CI/CD configuration file")
  • Display or hide the pipeline suggestion banner (renamed from "Pipeline suggestion banner")
  • Display or hide the Jenkins migration banner (renamed from "Jenkins migration banner")
• Set CI/CD limits

Future work

Additional MRs will be opened to apply these same documentation improvements to the remaining sections of the CI/CD settings page:

1. Package registry configuration section
2. Runners section
3. Job token permissions section
4. Job logs section

This phased approach allows for more focused reviews while ensuring consistency across the entire document.

Review app link

• https://docs.gitlab.com/upstream-review-mr-ee-189233/administration/settings/continuous_integration/#pipelines

References

• Pt. 1: Restructure CI/CD Admin settings documentation (!188635 - merged) (structural and organizational changes)
• Pt. 2: Improve CI/CD settings documentation (pt.2) (!189102 - merged) (improves continuous integration and delivery settings)

Screenshots or screen recordings

Before	After