scripted-diff: Following the C++ Standard rules for identifiers with _.

Any identifier starting with two _, or one _ followed by a capital letter is reserved for the compiler and thus must not be used. See: https://stackoverflow.com/a/228797/7130273

-BEGIN VERIFY SCRIPT-
s() { git grep -l "$1" src | xargs sed -i "s/$1/$2/g"; }

s '__pushKV' 'pushKVEnd'
s '_EraseTx' 'EraseTxNoLock'
s '_Other' 'Other'
-END VERIFY SCRIPT-

src/rpc/mempool.cpp

@@ -351,8 +351,8 @@ UniValue MempoolToJSON(const CTxMemPool& pool, bool verbose, bool include_mempoo
             entryToJSON(pool, info, e);
             // Mempool has unique entries so there is no advantage in using
             // UniValue::pushKV, which checks if the key already exists in O(N).
-            // UniValue::__pushKV is used instead which currently is O(1).
-            o.__pushKV(hash.ToString(), info);
+            // UniValue::pushKVEnd is used instead which currently is O(1).
+            o.pushKVEnd(hash.ToString(), info);
         }
         return o;
     } else {