Fix template making page scroll to Persona on load

What does this MR do?

Fix persona links to make page scroll to anchors on loading.

Current link: https://design.gitlab.com/research/personas#persona-sasha

Expected link: https://design.gitlab.com/research/personas/#persona-sasha

What are the relevant issue numbers?

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated via this MR
• Documentation reviewed by technical writer or follow-up review issue created
• Tests added for this feature/bug
• Tested in all supported browsers
• Conforms to the code review guidelines
• Conforms to the merge request performance guidelines
• Conforms to the style guides
• Conforms to the database guides
• Link to e2e tests MR added if this MR has Requires e2e tests label. See the Test Planning Process.
• Security reports checked/validated by reviewer