rpc: Documentation fixups

src/rpc/misc.cpp

@@ -461,7 +461,7 @@ static UniValue echo(const JSONRPCRequest& request)
         throw std::runtime_error(
             RPCHelpMan{"echo|echojson ...",
                 "\nSimply echo back the input arguments. This command is for testing.\n"
-                "\nThe difference between echo and echojson is that echojson has argument conversion enabled in the client-side table in"
+                "\nThe difference between echo and echojson is that echojson has argument conversion enabled in the client-side table in "
                 "bitcoin-cli and the GUI. There is no server-side difference.",
                 {}}
                 .ToString() +

test/lint/lint-rpc-help.sh

@@ -3,10 +3,17 @@
 # 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.
+#
+# Check that all RPC help texts are generated by RPCHelpMan.
 
 export LC_ALL=C
 
 EXIT_CODE=0
+
+# Assume that all multiline strings passed into a runtime_error are help texts.
+# This is potentially fragile, but the linter is only temporary and can safely
+# be removed early 2019.
+
 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:"