fix: gas from step 3 -> step 4

neps/nep-0539.md

@@ -175,10 +175,10 @@
     receipt_bytes: u64,
     allowed_shard: u32`,
    }
    ```
 2. (new) Compute bandwidth limits to other shards based on the congestion information.
    The formula is:
     ```python
     for receiver in other_shards:
       MAX_CONGESTION_INCOMING_GAS = 20 Pgas
       incoming_congestion = gas_backlog[receiver] / MAX_CONGESTION_INCOMING_GAS
@@ -204,7 +204,7 @@
         MAX_GAS_FORWARDING = 300 Pgas
         outgoing_gas_limit[receiver]
           = mix(MAX_GAS_FORWARDING, MIN_GAS_FORWARDING, congestion)
     ```
 3. (new) Drain receipts in the outgoing buffer from the previous round-
     - Subtract `receipt.gas()` from `outgoing_gas_limit[receipt.receiver]` for
       each receipt drained.
@@ -223,7 +223,7 @@
       the local shard.
 5. Execute receipts in the order of `local`, `delayed`, `incoming`, `yield-resume time-out`.
     - Don't stop before all receipts are executed or more than 1000 Tgas have
-      been burnt. Burnt gas includes the burnt gas from step 3.
+      been burnt. Burnt gas includes the burnt gas from step 4.
     - Outgoing receipts up to what is left in
       `outgoing_gas_limit[receipt.receiver]` per shard (after step 3) go to the
       outgoing receipts list of the chunk.
@@ -265,8 +265,8 @@
 
 We add two trie columns:
 
 * `BUFFERED_RECEIPT_INDICES: u8 = 13;`
 * `BUFFERED_RECEIPT: u8 = 14`
 
 The `BUFFERED_RECEIPT_INDICES` column only has one value, which stores a borsh-serialized instance of
 `BufferedReceiptIndices` defines as follows:
@@ -653,7 +653,7 @@
 ## Consequences
 
 
 ### 
 
 ### Positive