docs: specify that Balance is yoctoNEAR
@@ -25,7 +25,7 @@ pub type BlockHeight = u64;
pub type EpochHeight = u64;
/// Shard index, from 0 to NUM_SHARDS - 1.
pub type ShardId = u64;
-/// Balance is type for storing amounts of tokens.
+/// Balance is a type for storing amounts of tokens, specified in yoctoNEAR.
pub type Balance = u128;
/// Number of blocks in current group.
