Merge pull request 0xPolygon#322 from 0xPolygon/remove-pos-slashing-references

PoS: Update staking manager doc

Author: hsutaiyu

docs/img/pos/checkpoint.png

@@ -32,7 +32,7 @@ type CheckpointBlockHeader struct {
 
 #### Root hash calculation
 
-![Root Hash Image](../../../img/pos/checkpoint.svg)
+![Root Hash Image](../../../img/pos/checkpoint.png)
 
 The `RootHash` is calculated as a Merkle hash of Bor block hashes from `StartBlock` to `EndBlock`. The process involves hashing each block's number, time, transaction hash, and receipt hash, then creating a Merkle root of these hashes.
 
@@ -83,44 +83,41 @@ rootHash := tree.Root().Hash
 `AccountRootHash` is the hash of the validator account-related information that needs to pass to the Ethereum chain at each checkpoint.
 
 ```jsx
-eachAccountHash := keccak256([validator id, withdraw fee, slash amount])
+eachAccountHash := keccak256([validator id, withdraw fee])
 ```
 
 Pseudocode for the account root hash for `1` to `n` Bor blocks:
 
 ```go
-B(1) := keccak256([validator id, withdraw fee, slash amount])
-B(2) := keccak256([validator id, withdraw fee, slash amount])
+B(1) := keccak256([validator id, withdraw fee])
+B(2) := keccak256([validator id, withdraw fee])
 .
 .
 .
-B(n) := keccak256([validator id, withdraw fee, slash amount])
+B(n) := keccak256([validator id, withdraw fee])
 
 // account root hash is Merkle root of all block hash
 checkpoint's account root hash = Merkel[B(1), B(2), ....., B(n)]
 ```
 
-Golang code for the account hash can be found here: [https://github.com/maticnetwork/heimdall/blob/develop/types/dividend-account.go#L91-L101](https://github.com/maticnetwork/heimdall/blob/develop/types/dividend-account.go#L91-L101)
+Golang code for the account hash can be found here: [https://github.com/maticnetwork/heimdall/blob/develop/types/dividend-account.go](https://github.com/maticnetwork/heimdall/blob/develop/types/dividend-account.go)
 
 ```go
-// DividendAccount contains Fee, Slashed amount
+// DividendAccount contains burned Fee amount
 type DividendAccount struct {
- ID            DividendAccountID `json:"ID"`
- FeeAmount     string            `json:"feeAmount"`     // string representation of big.Int
- SlashedAmount string            `json:"slashedAmount"` // string representation of big.Int
+	User      HeimdallAddress `json:"user"`
+	FeeAmount string          `json:"feeAmount"` // string representation of big.Int
 }
 
-// calculate hash for particular account
+// CalculateHash hashes the values of a DividendAccount
 func (da DividendAccount) CalculateHash() ([]byte, error) {
- fee, _ := big.NewInt(0).SetString(da.FeeAmount, 10)
- slashAmount, _ := big.NewInt(0).SetString(da.SlashedAmount, 10)
- divAccountHash := crypto.Keccak256(appendBytes32(
-  new(big.Int).SetUint64(uint64(da.ID)).Bytes(),
-  fee.Bytes(),
-  slashAmount.Bytes(),
- ))
-
- return divAccountHash, nil
+	fee, _ := big.NewInt(0).SetString(da.FeeAmount, 10)
+	divAccountHash := crypto.Keccak256(appendBytes32(
+		da.User.Bytes(),
+		fee.Bytes(),
+	))
+
+	return divAccountHash, nil
 }
 ```
 

docs/img/pos/checkpoint.svg

@@ -25,20 +25,14 @@ PIP4 introduced the concept of showcasing validator performance for community vi
 
 ## Methods and variables
 
-!!!caution
-    Slashing Implementation
-
-    `jail`, `unJail`, and `slash` functions are not used currently as part of the slashing implementation.
-
-
 ### validatorThreshold
 
 It stores the maximum number of validators accepted by the system, also called slots.
 
 ### AccountStateRoot
 
 - For various accounting done on Heimdall for validators and delegator, account root is submitted while submitting the `checkpoint`.
-- accRoot is used while `claimRewards` and `unStakeClaim`.
+- `accRoot` is used while `claimRewards` and `unStakeClaim`.
 
 ### stake / stakeFor
 
@@ -76,9 +70,7 @@ function stakeFor(
 ```solidity
 function unstakeClaim(uint256 validatorId) public;
 ```
-
-- After `unstaking`, validators are put into withdrawal period so that they can be slashed, if any fraud found after `unstaking`, for past frauds.
-- Once `WITHDRAWAL_DELAY` period is served, validators can call this function and do settlement with `stakeManager` (get rewards if any, get staked tokens back, burn NFT, etc).
+Once `WITHDRAWAL_DELAY` period is served, validators can call this function and do settlement with `stakeManager` (get rewards if any, get staked tokens back, burn NFT, etc).
 
 ### restake
 
@@ -127,7 +119,7 @@ function claimFee(
 
 This method is used to withdraw fees from Heimdall. `accountStateRoot` is updated on each checkpoint, so that validators can provide proof of inclusion in this root for account on Heimdall and withdraw fee.
 
-Note that `accountStateRoot` is re-written to prevent exits on multiple checkpoints (for old root and save accounting on `stakeManager`). `accumSlashedAmount` is unused at the moment and will be used for slashing on Heimdall if needed.
+Note that `accountStateRoot` is re-written to prevent exits on multiple checkpoints (for old root and save accounting on `stakeManager`).
 
 ### StakingNFT