Update transactions.md (#3447)

Signed-off-by: 0xmbcode <[email protected]>

docs/protocol/src/concepts/transactions.md

@@ -1,7 +1,7 @@
 # Transactions
 
 Transactions describe an atomic collection of changes to the ledger state.  Each
-transaction consist of a sequence of *descriptions* for various actions[^1].
+transaction consists of a sequence of *descriptions* for various actions[^1].
 Each description adds or subtracts (typed) value from the transaction's value
 balance, which must net to zero.  Penumbra adapts the *Spend* and *Output* actions from Sapling, and adds many new descriptions to support additional functionality: