PIP-31: add pending consumptions

PIPs/pip-31.md

@@ -55,6 +55,7 @@ To understand the Consumptional Fee Model, we first need to define consumption.
 Transactions are sequences of bytes that validators decode, process, and store in their local database.
 Consumption is defined as the number of bytes stored over the last 8,640 blocks [^1]
 for a specific account that signed the transactions.
+If an account has any pending transactions in the pool, their size is also added to the account’s consumption.
 
 #### Coefficient
 
@@ -104,6 +105,9 @@ increasing the value for each address by the size of its transactions.
 Simultaneously, the block from 8640 blocks ago would be retrieved,
 and the value for each address would be decreased by the size of its transactions.
 
+To calculate pending consumption, we iterate over all transactions in the pool
+to determine the pending consumption for each specific account.
+
 #### New Account Detection
 
 To determine if an account is new and hasn't sent any transactions yet,