fix(magic-contracts): Add missing docstrings in magic contracts

[Ginowine]

Description of change

Some of the magic contract reference docs are missing information about using the functions. This PR adds Solidity docstrings to the functions of the following contracts:

• ISC
• ISCAccounts
• ISCPrivileged
• ISCSandbox
• ISCTypes
• ISCUtil

Links to any relevant issues

`fixes issue #3422

Type of change

• Documentation Fix

Change checklist

Tick the boxes that are relevant to your changes, and delete any items that are not.

• I have followed the contribution guidelines for this project
• I have performed a self-review of my own code
• I have selected the develop branch as the target branch

[salaheldinsoliman]

@Ginowine LGTM! except for this small comment:
NatSpec tags are all optional. That is, if @notice explains what the function does, there is no need to add a @dev. only add it when there are extra details
Can you please give it another small iteration, where if a @notice suffices just remove @dev
Thanks

[Ginowine]

@Ginowine LGTM! except for this small comment: NatSpec tags are all optional. That is, if @notice explains what the function does, there is no need to add a @dev. only add it when there are extra details Can you please give it another small iteration, where if a @notice suffices just remove @dev Thanks

@salaheldinsoliman. Ok great, thanks. I'll go through it again.

[lucas-tortora]

could you rename the PR to follow the guidelines on confluence?