Merge bitcoin#23714: doc: Normalize RPC description whitespace

faa0833 doc: Normalize RPC description whitespace (MarcoFalke)

Pull request description:

  It is tedious to manually add trailing newlines after the description so that there is an empty new line before the `Arguments` section.

  Fix that by adding it with C++ code.

ACKs for top commit:
  fanquake:
    ACK faa0833

Tree-SHA512: 061786c7f19d767f2b7a0362b948e34d181f4cc740a60211756da29ece7554e95be39a9beec3e201eddc8da3ea7e22ac917479eae04b230bb7b0db7a9647af8c

Author: fanquake

src/rpc/misc.cpp

@@ -301,7 +301,7 @@ static RPCHelpMan deriveaddresses()
 static RPCHelpMan verifymessage()
 {
     return RPCHelpMan{"verifymessage",
-                "\nVerify a signed message\n",
+                "Verify a signed message.",
                 {
                     {"address", RPCArg::Type::STR, RPCArg::Optional::NO, "The bitcoin address to use for the signature."},
                     {"signature", RPCArg::Type::STR, RPCArg::Optional::NO, "The signature provided by the signer in base 64 encoding (see signmessage)."},

src/rpc/util.cpp

@@ -620,10 +620,9 @@ std::string RPCHelpMan::ToString() const
         ret += arg.ToString(/* oneline */ true);
     }
     if (was_optional) ret += " )";
-    ret += "\n";
 
     // Description
-    ret += m_description;
+    ret += "\n\n" + TrimString(m_description) + "\n";
 
     // Arguments
     Sections sections;

test/functional/rpc_generate.py

@@ -17,9 +17,9 @@ def set_test_params(self):
 
     def run_test(self):
         message = (
-            "generate\n"
+            "generate\n\n"
             "has been replaced by the -generate "
-            "cli option. Refer to -help for more information."
+            "cli option. Refer to -help for more information.\n"
         )
 
         self.log.info("Test rpc generate raises with message to use cli option")