OKR: Improve CI/CD/General pipelines settings-related UI text

Update UI text to meet our style guidelines

Resolves #298822 (closed)
Resolves #21956 (closed)

Update this section of the UI to meet the Pajamas style guidelines: Settings > CI/CD > General pipelines.

Changes

• Simplifies the project settings text significantly, as per the rules below. Also updates one group setting to match.
• Adds a docs link for Git shallow clone setting
• Removes examples from the settings:
  • Public pipelines setting details are repeating what's already in the docs. Best to have a SSoT, so deleted and relying on the docs.
  • Coverage regex examples should be in the docs as a SSoT, and also to make future contributions of regex patterns easier for contributors. Moved to the docs.
• Removes Pending from the Auto-cancel redundant, pending pipelines setting, as it's repetitive.
• With the removal of the large (blue) text blocks, I moved three settings to the top of the section, as I think they make more sense at the top, and allows the large settings to not be split up in the middle.

Review grammar and style

At a minimum, address these issues:

• Present tense rather than future. https://design.gitlab.com/content/voice-tone#instructions
• Active voice. https://design.gitlab.com/content/voice-tone#active-voice
• No periods for settings or headings. https://design.gitlab.com/content/punctuation#periods
• Periods for all help text.
• No repetitive or unnecessary text. (Things like: This setting is... or "Use this setting to.")
• Oxford comma used correctly. (This, this, and this.)
• Language is parallel. (Review all the settings in the section to ensure they are similarly-worded.) https://design.gitlab.com/content/voice-tone#parallelism
• If a setting is optional, then "optional" is in parentheses at the end of the setting name. https://design.gitlab.com/components/form/#required-information
• Latinisms (i.e., e.g.) removed. https://design.gitlab.com/content/voice-tone#avoid-latin-abbreviations
• Don't use "allow" unless you're specifically talking about security. For example, "Allows users to fork the repo" should be "Users can fork the repo."
• Do a final review of everything you've updated and consider whether it affects the docs. If it does, open a follow-up issue or an MR to update the docs.
• If you have a link to documentation, attempt to refer to the link as a question (like, "How do I configure runners?"). If not possible, use "Learn more." https://design.gitlab.com/usability/helping-users#formatting-help-content

Screenshots (larger below)

Before	After

Before

After

Related to #298822 (closed)