Make sure docs are up to date respect to controller deprecation plan

[IkerAlus]

In runtime v9430, certain changes are pushed to the staking pallet as part of the Staking Controller Deprecation Plan. Mainly these changes are:

• set_controller: Removes the controller argument, and changes the logic to always set the controller to a staker’s stash account.
• bond: Removes the controller argument, and also changes the logic to always set controller to the stash.

Hence from v9430 users will not be able to a different controller for their stash account, this issue is created just to make sure this is taking into account in SIdecar's docs and endpoint descrptions once v9430 is released.