Merge #16900: doc: Fix doxygen comment for SignTransaction in rpc/rawtransaction_util

fa8d65f doc: Fix doxygen comment for SignTransaction in rpc/rawtransaction_util (MarcoFalke)

Pull request description:

  The param `coins` to `SignTransaction` is final and can thus not be extended (as suggested by the doc).

ACKs for top commit:
  practicalswift:
    ACK fa8d65f -- const correctness is good and diff looks correct
  fanquake:
    ACK fa8d65f

Tree-SHA512: 041e159f2c3cf96e296173c31f3e5f35bbc7711cc888aa4bf08aaa8c65c95ee7f7672f65396690a9af45795a618eea0fadde7fb02d29ec85f1b4df5e6d9e0c7a

Author: fanquake

src/rpc/rawtransaction_util.cpp

@@ -268,7 +268,7 @@ void ParsePrevouts(const UniValue& prevTxsUnival, FillableSigningProvider* keyst
     }
 }
 
-UniValue SignTransaction(CMutableTransaction& mtx, const SigningProvider* keystore, std::map<COutPoint, Coin>& coins, const UniValue& hashType)
+UniValue SignTransaction(CMutableTransaction& mtx, const SigningProvider* keystore, const std::map<COutPoint, Coin>& coins, const UniValue& hashType)
 {
     int nHashType = ParseSighashString(hashType);
 

src/rpc/rawtransaction_util.h

@@ -19,11 +19,11 @@ class SigningProvider;
  *
  * @param  mtx           The transaction to-be-signed
  * @param  keystore      Temporary keystore containing signing keys
- * @param  coins         Map of unspent outputs - coins in mempool and current chain UTXO set, may be extended by previous txns outputs after call
+ * @param  coins         Map of unspent outputs
  * @param  hashType      The signature hash type
  * @returns JSON object with details of signed transaction
  */
-UniValue SignTransaction(CMutableTransaction& mtx, const SigningProvider* keystore, std::map<COutPoint, Coin>& coins, const UniValue& hashType);
+UniValue SignTransaction(CMutableTransaction& mtx, const SigningProvider* keystore, const std::map<COutPoint, Coin>& coins, const UniValue& hashType);
 
 /**
   * Parse a prevtxs UniValue array and get the map of coins from it