Dispute distribution guide (#3158)

* Dispute distribution initial design.

* WIP.

* Dispute distribution guide update.

* Make invalid statement include `InvalidStatementKind`.

* Clarify the scope of disputes.

* A few fixes + introduced back pressure oneshot.

* Fixes and spam protection WIP.

* More spam considerations.

* More fixes.

* Fixes + add note about not dispute participating nodes.

polkadot/node/network/protocol/src/lib.rs

@@ -302,7 +302,7 @@ pub mod v1 {
 		UncheckedSignedFullStatement,
 	};
 
-	
+
 	/// Network messages used by the bitfield distribution subsystem.
 	#[derive(Debug, Clone, Encode, Decode, PartialEq, Eq)]
 	pub enum BitfieldDistributionMessage {