This commit aims to fix the broken markdown links to pass the checker and updates the sidebar structure/titles of pages to add clarification.

Signed-off-by: Sunil Singh <sunil.singh@suse.com>

versioned_sidebars/version-2.8-sidebars.json

@@ -1305,6 +1305,7 @@
       "label": "Rancher Kubernetes API",
       "items": [
         "api/quickstart",
+        "api/v3-rancher-api-guide",
         {
           "type": "category",
           "label": "Example Workflows",
@@ -1312,9 +1313,8 @@
             "api/workflows/projects"
           ]
         },
-        "api/api-reference",
         "api/api-tokens",
-        "api/previous-rancher-api-versions"
+        "api/api-reference"
       ]
     },
     "contribute-to-rancher"