refactor: Hand-replace some ParseHex -> ""_hex

The following scripted-diff commit will replace ParseHex("...") with "..."_hex_u8, but this replacement will not work in cases where vectors are needed instead of arrays, and is not ideal in cases where std::byte is accepted.

For example, it is currently necessary to use _hex_v_u8 when calling CScript operator<< because that operator does not currently support std::array or std::byte.

Conversely, it is incorrect to use _hex_v instead of _hex in net_processing.cpp for the MakeAndPushMessage argument, because if the argument is a std::vector it is considered variable-length and serialized with a size prefix, but if the argument is a std::array or Span is it considered fixed length and serialized without a prefix.

By the same logic, it is also safe to change the NUMS_H constant in pubkey.cpp from a std::vector to std::array because it is never serialized.

src/wallet/test/ismine_tests.cpp

@@ -15,6 +15,7 @@
 
 #include <boost/test/unit_test.hpp>
 
+using namespace util::hex_literals;
 
 namespace wallet {
 BOOST_FIXTURE_TEST_SUITE(ismine_tests, BasicTestingSetup)
@@ -683,7 +684,7 @@ BOOST_AUTO_TEST_CASE(ismine_standard)
         BOOST_CHECK(keystore.GetLegacyScriptPubKeyMan()->AddKey(keys[0]));
 
         scriptPubKey.clear();
-        scriptPubKey << OP_0 << ToByteVector(ParseHex("aabb"));
+        scriptPubKey << OP_0 << "aabb"_hex_v_u8;
 
         result = keystore.GetLegacyScriptPubKeyMan()->IsMine(scriptPubKey);
         BOOST_CHECK_EQUAL(result, ISMINE_NO);
@@ -698,7 +699,7 @@ BOOST_AUTO_TEST_CASE(ismine_standard)
         BOOST_CHECK(keystore.GetLegacyScriptPubKeyMan()->AddKey(keys[0]));
 
         scriptPubKey.clear();
-        scriptPubKey << OP_16 << ToByteVector(ParseHex("aabb"));
+        scriptPubKey << OP_16 << "aabb"_hex_v_u8;
 
         result = keystore.GetLegacyScriptPubKeyMan()->IsMine(scriptPubKey);
         BOOST_CHECK_EQUAL(result, ISMINE_NO);