Note: Doc team updates the current version of the documentation and the
two previous versions (n-2), but we address *only high-priority, or
customer-reported issues* for -2 releases in support.
Describe the changes in the doc and link to your dev story:

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

2. - [x] Mandatory: Choose the type of documentation change or review.

• [x] We need to update to an existing topic

3. - [x] *Mandatory: *Use the following link to open the doc and find where the
documentation update should go. Note: As the feature and doc is
understood and developed, this placement decision may change:

https://docs.redhat.com/en/documentation/red_hat_advanced_cluster_management_for_kubernetes/2.11/html/clusters/cluster_mce_overview#on-prem-creating-your-cluster-with-the-cli-agentclusterinstall

4. - [ ] Mandatory for GA content:

... N/A this is a bug.

5. - [x] Mandatory for bugs: What is the diff? Clearly define what the
problem is, what the change is, and link to the current documentation. Only
use this for a documentation bug.

Add documentation for the AgentClusterInstall "Proxy" spec field:

GROUP:      extensions.hive.openshift.io
KIND:       AgentClusterInstall
VERSION:    v1beta1

FIELD: proxy <Object>

DESCRIPTION:
    Proxy defines the proxy settings used for the install config
    
FIELDS:
  httpProxy	<string>
    HTTPProxy is the URL of the proxy for HTTP requests.

  httpsProxy	<string>
    HTTPSProxy is the URL of the proxy for HTTPS requests.

  noProxy	<string>
    NoProxy is a comma-separated list of domains and CIDRs for which the proxy
    should not be used.

Specifically either the AgentClusterInstall used in the example should contain the proxy fields (as the following InfraEnv resource does) or a new section/doc should be created for advanced configuration to describe optional fields.