fix: add flowtype for SignaturePubkeyPair

web3.js/module.flow.js

@@ -110,6 +110,11 @@ declare module '@solana/web3.js' {
     userdata: Buffer;
   }
 
+  declare type SignaturePubkeyPair = {|
+    signature: Buffer | null,
+    publicKey: PublicKey,
+  |};
+
   declare type TransactionCtorFields = {|
     fee?: number,
     lastId?: TransactionId,

web3.js/src/transaction.js

@@ -62,6 +62,14 @@ export class TransactionInstruction {
   }
 }
 
+/**
+ * @private
+ */
+type SignaturePubkeyPair = {|
+  signature: Buffer | null,
+  publicKey: PublicKey,
+|};
+
 /**
  * List of Transaction object fields that may be initialized at construction
  *
@@ -77,14 +85,6 @@ type TransactionCtorFields = {|
   signatures?: Array<SignaturePubkeyPair>,
 |};
 
-/**
- * @private
- */
-type SignaturePubkeyPair = {|
-  signature: Buffer | null,
-  publicKey: PublicKey,
-|};
-
 /**
  * Transaction class
  */