Create an informative issue (See each section, incomplete templates/issues won't be triaged)

There are 3 things we expect to be change under: https://github.com/stolostron/rhacm-docs/blob/2.10_stage/apis/api.adoc

#1 the https://github.com/stolostron/rhacm-docs/blob/2.10_stage/apis/clusterset.json.adoc#clustersets-api and https://github.com/stolostron/rhacm-docs/blob/2.10_stage/apis/managedclusterset.json.adoc#managedclusterset-api  are actually points to one API managedclusterset. We expect remove the duplication link.
The managedclusterset is a cluster scoped CR, so description in this page is not accurate as well.

#2 Change Clusters API to ManagedClusters API https://github.com/stolostron/rhacm-docs/blob/2.10_stage/apis/cluster.json.adoc#clusters-api

#3 Change ClusterSetBindings API to ManagedClusterSetBindings API https://github.com/stolostron/rhacm-docs/blob/2.10_stage/apis/clustersetbinding.json.adoc#clustersetbindings-api

Renaming is aim to avoid misunderstanding in the future, the #1 should be fixed in both 2.9 and 2.10, the #2 and #3 can only be fixed in 2.10.

Prerequisite: Start with what we have

Always look at the current documentation to describe the change that is needed. Use the source or portal link for Step 4:

 - Use the Customer Portal: https://access.redhat.com/documentation/en-us/red_hat_advanced_cluster_management_for_kubernetes

 - Use the GitHub link to find the staged docs in the repository: https://github.com/stolostron/rhacm-docs 

Describe the changes in the doc and link to your dev story

Provide info for the following steps:

1. - [x] Mandatory Add the required version to the Fix version/s field.

2. - [ ] Mandatory Choose the type of documentation change.

      - [ ] New topic in an existing section or new section
      - [x] Update to an existing topic

3. - [ ] Mandatory for GA content:
            
       - [ ] Add steps and/or other important conceptual information here: 
       
            
       - [ ] Add Required access level for the user to complete the task here:
       

       - [ ] Add verification at the end of the task, how does the user verify success (a command to run or a result to see?)
     
     
       - [ ] Add link to dev story here:

4. - [x] Mandatory for bugs: What is the diff? Clearly define what the problem is, what the change is, and link to the current documentation: