[Improvement][45_Timelock] question regarding visibility setting of changeAdmin function

[smallfu6]

Description

In the Timelock contract, the changeAdmin function is currently set to public, and it uses the onlyTimelock modifier to ensure that only the contract itself can call this function. I believe it would be more appropriate to set the changeAdmin function to private.

/**
 * @dev 改变管理员地址，调用者必须是Timelock合约。
 */
function changeAdmin(address newAdmin) public onlyTimelock {
        admin = newAdmin;

        emit NewAdmin(newAdmin);
 }

Are you willing to submit a PR?(你愿意提交PR吗？)

• [X] Yes I am willing to submit a PR!(是的我愿意)

[XdpCs]

public onlyTimelock == private I think public onlyTimelock will be clearer, private needs more info to explain why it is private.

[XdpCs]

If you have any questions, you can reopen this issue.