test: Suggested cleanups for rpc_namedparams test

No changes in behavior, just implements review suggestions from

bitcoin#19762 (comment)
bitcoin#19762 (comment)
bitcoin#26628 (comment)

src/test/rpc_tests.cpp

@@ -84,7 +84,7 @@ BOOST_FIXTURE_TEST_SUITE(rpc_tests, RPCTestingSetup)
 
 BOOST_AUTO_TEST_CASE(rpc_namedparams)
 {
-    const std::vector<std::string> arg_names{{"arg1", "arg2", "arg3", "arg4", "arg5"}};
+    const std::vector<std::string> arg_names{"arg1", "arg2", "arg3", "arg4", "arg5"};
 
     // Make sure named arguments are transformed into positional arguments in correct places separated by nulls
     BOOST_CHECK_EQUAL(TransformParams(JSON(R"({"arg2": 2, "arg4": 4})"), arg_names).write(), "[null,2,null,4]");
@@ -104,7 +104,7 @@ BOOST_AUTO_TEST_CASE(rpc_namedparams)
     BOOST_CHECK_EXCEPTION(TransformParams(JSON(R"({"args": [1,2,3], "arg4": 4, "arg2": 2})"), arg_names), UniValue,
                           HasJSON(R"({"code":-8,"message":"Parameter arg2 specified twice both as positional and named argument"})"));
 
-    // Make sure extra positional arguments can be passed through to the method implemenation, as long as they don't overlap with named arguments.
+    // Make sure extra positional arguments can be passed through to the method implementation, as long as they don't overlap with named arguments.
     BOOST_CHECK_EQUAL(TransformParams(JSON(R"({"args": [1,2,3,4,5,6,7,8,9,10]})"), arg_names).write(), "[1,2,3,4,5,6,7,8,9,10]");
     BOOST_CHECK_EQUAL(TransformParams(JSON(R"([1,2,3,4,5,6,7,8,9,10])"), arg_names).write(), "[1,2,3,4,5,6,7,8,9,10]");
 }