Update document link

[alpercun]

This pr corrects the incorrect document link.

• Please check if the PR fulfills these requirements

• [x] The commit message follows our guidelines
• [ ] Tests for the changes have been added (for bug fixes / features)
• [x] Docs have been added / updated (for bug fixes / features)

• Other information: This pr corrects the incorrect document link. #122

[klmhyeonwoo]

For first-time visitors, wouldn't the "https://wopehq.github.io/vue3-tree/guide/#installation" link be appropriate? And I think this address is most relevant to the title of the section.