Merge bitcoin/bitcoin#27822: Renamed UniValue::__pushKV to UniValue::pushKVEnd.

bdea2bb114 scripted-diff: Following the C++ Standard rules for identifiers with _. (Brotcrunsher)

Pull request description:

  Any identifier starting with 2 _ is reserved for the compiler and thus must not be used.

  See: https://stackoverflow.com/a/228797/7130273

ACKs for top commit:
  MarcoFalke:
    lgtm ACK bdea2bb114

Tree-SHA512: 74c8e676449f3f61476d846bfd2c514103c8914e13c4a0db841203abdc0267c25ddc6ed57d6791459efe3edea17753a1b53c3795071ddfe8aba8662521063407

src/test/settings_tests.cpp

@@ -35,7 +35,7 @@ inline std::ostream& operator<<(std::ostream& os, const common::SettingsValue& v
 inline std::ostream& operator<<(std::ostream& os, const std::pair<std::string, common::SettingsValue>& kv)
 {
     common::SettingsValue out(common::SettingsValue::VOBJ);
-    out.__pushKV(kv.first, kv.second);
+    out.pushKVEnd(kv.first, kv.second);
     os << out.write();
     return os;
 }