Update capitalization in /dev docs

What does this MR do?

Fixes some of the common capitalization issues in docs, this time in:

• /development
• /gitlab-basics
• /install

This is in preparation for someday enabling a capitalization test in markdownlint. The search array used was:

  "proper-names": {
    "names": [
      "Git",
      "GitLab",
      "JavaScript",
      "Jira",
      "Jenkins",
      "GitLab Runner",
      "Kubernetes",
      "Debian",
      "Ubuntu",
      "GitLab Shell",
      "Omnibus GitLab"
    ],
    "code_blocks": false
  }

Related issues

Related to gitlab#31185 (closed)

Author's checklist

• Follow the Documentation Guidelines and Style Guide.
• Link docs to and from the higher-level index page, plus other related docs where helpful.
• Apply the ~Documentation label.

Review checklist

All reviewers can help ensure accuracy, clarity, completeness, and adherence to the Documentation Guidelines and Style Guide.

1. Primary Reviewer

• Review by a code reviewer or other selected colleague to confirm accuracy, clarity, and completeness. This can be skipped for minor fixes without substantive content changes.

2. Technical Writer

• Optional: Technical writer review. If not requested for this MR, must be scheduled post-merge. To request for this MR, assign the writer listed for the applicable DevOps stage.

3. Maintainer

1. Review by assigned maintainer, who can always request/require the above reviews. Maintainer's review can occur before or after a technical writer review.
2. Ensure a release milestone is set and that you merge the equivalent EE MR before the CE MR if both exist.
3. If there has not been a technical writer review, create an issue for one using the Doc Review template.