qa: unify unix epoch time descriptions

to "UNIX epoch time".

Call sites updated:
```
mocktime
getblockheader
getblock
pruneblockchain
getchaintxstats
getblocktemplate
setmocktime
getpeerinfo
setban
getnodeaddresses
getrawtransaction
importmulti
listtransactions
listsinceblock
gettransaction
getwalletinfo
getaddressinfo
```

2 files changed, 7 insertions, 7 deletions

diff --git a/src/wallet/rpcdump.cpp b/src/wallet/rpcdump.cpp
index d95481500d..633ac1b16d 100644
--- a/src/wallet/rpcdump.cpp
+++ b/src/wallet/rpcdump.cpp
@@ -1286,7 +1286,7 @@ UniValue importmulti(const JSONRPCRequest& mainRequest)
                                     {"scriptPubKey", RPCArg::Type::STR, RPCArg::Optional::NO, "Type of scriptPubKey (string for script, json for address). Should not be provided if using a descriptor",
                                         /* oneline_description */ "", {"\"<script>\" | { \"address\":\"<address>\" }", "string / json"}
                                     },
-                                    {"timestamp", RPCArg::Type::NUM, RPCArg::Optional::NO, "Creation time of the key in seconds since epoch (Jan 1 1970 GMT),\n"
+                                    {"timestamp", RPCArg::Type::NUM, RPCArg::Optional::NO, "Creation time of the key expressed in " + UNIX_EPOCH_TIME + ",\n"
         "                                                              or the string \"now\" to substitute the current synced blockchain time. The timestamp of the oldest\n"
         "                                                              key will determine how far back blockchain rescans need to begin for missing wallet transactions.\n"
         "                                                              \"now\" can be specified to bypass scanning, for keys which are known to never have been used, and\n"
diff --git a/src/wallet/rpcwallet.cpp b/src/wallet/rpcwallet.cpp
index d906f6ddf0..63cbe02b17 100644
--- a/src/wallet/rpcwallet.cpp
+++ b/src/wallet/rpcwallet.cpp
@@ -1374,14 +1374,14 @@ static const std::string TransactionDescriptionString()
            "    \"blockhash\": \"hashvalue\",                  (string) The block hash containing the transaction.\n"
            "    \"blockheight\": n,                          (numeric) The block height containing the transaction.\n"
            "    \"blockindex\": n,                           (numeric) The index of the transaction in the block that includes it.\n"
-           "    \"blocktime\": xxx,                          (numeric) The block time in seconds since epoch (1 Jan 1970 GMT).\n"
+           "    \"blocktime\": xxx,                          (numeric) The block time expressed in " + UNIX_EPOCH_TIME + ".\n"
            "    \"txid\": \"transactionid\",                   (string) The transaction id.\n"
            "    \"walletconflicts\": [                       (array) Conflicting transaction ids.\n"
            "      \"txid\",                                  (string) The transaction id.\n"
            "      ...\n"
            "    ],\n"
-           "    \"time\": xxx,                               (numeric) The transaction time in seconds since epoch (midnight Jan 1 1970 GMT).\n"
-           "    \"timereceived\": xxx,                       (numeric) The time received in seconds since epoch (midnight Jan 1 1970 GMT).\n"
+           "    \"time\": xxx,                               (numeric) The transaction time expressed in " + UNIX_EPOCH_TIME + ".\n"
+           "    \"timereceived\": xxx,                       (numeric) The time received expressed in " + UNIX_EPOCH_TIME + ".\n"
            "    \"comment\": \"...\",                          (string) If a comment is associated with the transaction, only present if not empty.\n"
            "    \"bip125-replaceable\": \"yes|no|unknown\",    (string) Whether this transaction could be replaced due to BIP125 (replace-by-fee);\n"
            "                                                     may be unknown for unconfirmed transactions not in the mempool\n";
@@ -2428,10 +2428,10 @@ static UniValue getwalletinfo(const JSONRPCRequest& request)
             "  \"unconfirmed_balance\": xxx,        (numeric) DEPRECATED. Identical to getbalances().mine.untrusted_pending\n"
             "  \"immature_balance\": xxxxxx,        (numeric) DEPRECATED. Identical to getbalances().mine.immature\n"
             "  \"txcount\": xxxxxxx,                (numeric) the total number of transactions in the wallet\n"
-            "  \"keypoololdest\": xxxxxx,           (numeric) the timestamp (seconds since Unix epoch) of the oldest pre-generated key in the key pool\n"
+            "  \"keypoololdest\": xxxxxx,           (numeric) the " + UNIX_EPOCH_TIME + " of the oldest pre-generated key in the key pool\n"
             "  \"keypoolsize\": xxxx,               (numeric) how many new keys are pre-generated (only counts external keys)\n"
             "  \"keypoolsize_hd_internal\": xxxx,   (numeric) how many new keys are pre-generated for internal use (used for change outputs, only appears if the wallet is using this feature, otherwise external keys are used)\n"
-            "  \"unlocked_until\": ttt,             (numeric) the timestamp in seconds since epoch (midnight Jan 1 1970 GMT) that the wallet is unlocked for transfers, or 0 if the wallet is locked\n"
+            "  \"unlocked_until\": ttt,             (numeric) the " + UNIX_EPOCH_TIME + " until which the wallet is unlocked for transfers, or 0 if the wallet is locked\n"
             "  \"paytxfee\": x.xxxx,                (numeric) the transaction fee configuration, set in " + CURRENCY_UNIT + "/kB\n"
             "  \"hdseedid\": \"<hash160>\"            (string, optional) the Hash160 of the HD seed (only present when HD is enabled)\n"
             "  \"private_keys_enabled\": true|false (boolean) false if privatekeys are disabled for this wallet (enforced watch-only wallet)\n"
@@ -3743,7 +3743,7 @@ UniValue getaddressinfo(const JSONRPCRequest& request)
             "                                                         hdseedid) and relation to the wallet (ismine, iswatchonly).\n"
             "  \"iscompressed\" : true|false,        (boolean, optional) If the pubkey is compressed.\n"
             "  \"label\" :  \"label\"                  (string) The label associated with the address. Defaults to \"\". Equivalent to the name field in the labels array.\n"
-            "  \"timestamp\" : timestamp,            (number, optional) The creation time of the key if available, expressed in seconds since Epoch Time (Jan 1 1970 GMT).\n"
+            "  \"timestamp\" : timestamp,            (number, optional) The creation time of the key, if available, expressed in " + UNIX_EPOCH_TIME + ".\n"
             "  \"hdkeypath\" : \"keypath\"             (string, optional) The HD keypath, if the key is HD and available.\n"
             "  \"hdseedid\" : \"<hash160>\"            (string, optional) The Hash160 of the HD seed.\n"
             "  \"hdmasterfingerprint\" : \"<hash160>\" (string, optional) The fingerprint of the master key.\n"