Update the "Communication Guidelines" link and corresponding text on the "Paid time off" page.
This includes a few changes for what is currently the sixth item under https://about.gitlab.com/handbook/paid-time-off/#a-gitlab-team-members-guide-to-time-off:
- The "Communication Guidelines" link text is now "Communicating Your Time Off" because that's the name of the section to which it links.
- That link's absolute URL has been simplified to be just the fragment identifier since it leads to content on the same page.
- "using the" is now "following the guidance under" because that makes more sense.
- "Jury Duty" is now "jury duty".