lint: Must use RPCHelpMan to generate the RPC docs

test/lint/lint-rpc-help.sh

@@ -0,0 +1,17 @@
+#!/usr/bin/env bash
+#
+# Copyright (c) 2018 The Bitcoin Core developers
+# Distributed under the MIT software license, see the accompanying
+# file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+export LC_ALL=C
+
+EXIT_CODE=0
+non_autogenerated_help=$(grep --perl-regexp --null-data --only-matching 'runtime_error\(\n\s*".*\\n"\n' $(git ls-files -- "*.cpp"))
+if [[ ${non_autogenerated_help} != "" ]]; then
+    echo "Must use RPCHelpMan to generate the help for the following RPC methods:"
+    echo "${non_autogenerated_help}"
+    echo
+    EXIT_CODE=1
+fi
+exit ${EXIT_CODE}