fix minor issue in BallotProtocol.h comments

[JuI3s]

Description

The comment documentation for the BallotProtocol seems to refer to Slot.

/**
 * The Slot object is in charge of maintaining the state of the SCP protocol
 * for a given slot index.
 */
class BallotProtocol
{
...
}

/**
 * The Slot object is in charge of maintaining the state of the SCP protocol
 * for a given slot index.
 */
class Slot : public std::enable_shared_from_this<Slot>
{
...
}

Checklist

• Reviewed the contributing document
• Rebased on top of master (no merge commits)
• Ran clang-format v8.0.0 (via make format or the Visual Studio extension)
• Compiles
• Ran all tests
• If change impacts performance, include supporting evidence per the performance document

[mbsdf]

@JuI3s last commit is not related to this PR, can you remove it and only keep the BallotProtocl.h change.

[JuI3s]

@JuI3s last commit is not related to this PR, can you remove it and only keep the BallotProtocl.h change.

Fixed it!

[mbsdf]

r+ c9e50b9

[MonsieurNicolas]

r+ c9e50b9