Complete normalization pass for Admin > Settings UI items

This normalization/review pass of the Admin Area portion of the Settings UI items should address the following items, to ensure the UI items updated in previous Settings UI work meet these criteria:

• 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."
• If there's a documentation link, 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

Efforts will focus on these style items, and not on content changes (unless there are marked, notable differences across the page that need to be addressed, or there are blatant errors).

Deliverable

The deliverable for this issue is based on the completed review of all Settings UI items in the Admin Area portion of GitLab's Settings. If any needed changes or updates are identified, the deliverable for this issue also requires that MRs are created for those changes, and that they're linked to this issue.

Prioritization

Each issue noted has been notated with a priority rating.

• 1️⃣ Highest priority
• 2️⃣ Medium priority
• 3️⃣ Low priority (cosmetic only)