[v10.4.x] Docs: g11 preview whats new fixes (#85762)

Docs: g11 preview whats new fixes (#85759)

* Made style fixes to intro

* Updated upgrade guide menu title

* Commented Explore metrics docs link back in

(cherry picked from commit 8014665ab5)

Co-authored-by: Isabel Matwawana <76437239+imatwawana@users.noreply.github.com>

docs/sources/upgrade-guide/upgrade-v11.0/index.md

@@ -8,7 +8,7 @@ keywords:
   - '11.0'
   - '11.0-preview'
 title: Upgrade to Grafana v11.0-preview
-menuTitle: Upgrade to v11.0
+menuTitle: Upgrade to v11.0-preview
 weight: 1200
 ---