core: document trimmed transactions better

Eventually we can drop them, but they were present for a long long time.

Signed-off-by: Roman Khimov <roman@nspcc.ru>

pkg/core/block/block.go

@@ -35,7 +35,9 @@ type Block struct {
 	// Transaction list.
 	Transactions []*transaction.Transaction
 
-	// True if this block is created from trimmed data.
+	// True if this block is created from trimmed data (with a proper
+	// header and hashes-only transactions). Not a part of a real
+	// block and is used only by internal packages.
 	Trimmed bool
 }
 

pkg/core/transaction/transaction.go

@@ -75,7 +75,7 @@ type Transaction struct {
 	hashed bool
 
 	// Trimmed indicates this is a transaction from trimmed
-	// data.
+	// data, meaning it doesn't have anything but hash.
 	Trimmed bool
 }