Merge #20169: Taproot follow-up: Make ComputeEntrySchnorr and ComputeEntryECDSA const to clarify contract

5136567 script: Make ComputeEntrySchnorr and ComputeEntryECDSA const to clarify contract (practicalswift)

Pull request description:

  Make `ComputeEntrySchnorr` and `ComputeEntryECDSA` `const` to clarify contract.

ACKs for top commit:
  benthecarman:
    ACK 5136567
  theStack:
    ACK 5136567 👌
  sipa:
    utACK 5136567

Tree-SHA512: 0f7a72bf6df7a97d21045ead9db398d2a9527c358aeeb894dec34a5386da4cc316e2f3326716e960ef8aa47bf73b99d1f92bb6d45dfa7871c84624bcad8a79f1

Author: fanquake

src/script/sigcache.cpp

@@ -46,14 +46,14 @@ class CSignatureCache
     }
 
     void
-    ComputeEntryECDSA(uint256& entry, const uint256 &hash, const std::vector<unsigned char>& vchSig, const CPubKey& pubkey)
+    ComputeEntryECDSA(uint256& entry, const uint256 &hash, const std::vector<unsigned char>& vchSig, const CPubKey& pubkey) const
     {
         CSHA256 hasher = m_salted_hasher_ecdsa;
         hasher.Write(hash.begin(), 32).Write(&pubkey[0], pubkey.size()).Write(&vchSig[0], vchSig.size()).Finalize(entry.begin());
     }
 
     void
-    ComputeEntrySchnorr(uint256& entry, const uint256 &hash, Span<const unsigned char> sig, const XOnlyPubKey& pubkey)
+    ComputeEntrySchnorr(uint256& entry, const uint256 &hash, Span<const unsigned char> sig, const XOnlyPubKey& pubkey) const
     {
         CSHA256 hasher = m_salted_hasher_schnorr;
         hasher.Write(hash.begin(), 32).Write(&pubkey[0], pubkey.size()).Write(sig.data(), sig.size()).Finalize(entry.begin());