Merge bitcoin#17831: rpc: doc: Fix and extend getblockstats examples

7099984 rpc: doc: Fix and extend getblockstats examples (Adam Soltys)

Pull request description:

  This pull fixes the example curl command for `getblockstats` which doesn't work as is because it's missing a comma between the params and has single quotes around the second parameter.

  It also adds an additional example of getting block stats by hash by using a known workaround (bitcoin#15412) to get bitcoin-cli to treat the hash parameter as JSON instead of a string since there is ongoing deliberation about how or whether to fix the root issue (bitcoin#15448).

ACKs for top commit:
  theStack:
    ACK bitcoin@7099984

Tree-SHA512: 84a5b7f449f06fff785bc0afbc1a7dfd55454bc76c52a8945e91556f87f3edfdc5a1780faab8fcfd6c415b734295b7c67d2e04ba7b6cfa91a77758af5dda53ae

src/rpc/blockchain.cpp

@@ -2071,8 +2071,10 @@ static UniValue getblockstats(const JSONRPCRequest& request)
             "}\n"
                 },
                 RPCExamples{
-                    HelpExampleCli("getblockstats", "1000 '[\"minfeerate\",\"avgfeerate\"]'")
-            + HelpExampleRpc("getblockstats", "1000 '[\"minfeerate\",\"avgfeerate\"]'")
+                    HelpExampleCli("getblockstats", R"('"00000000c937983704a73af28acdec37b049d214adbda81d7e2a3dd146f6ed09"' '["minfeerate","avgfeerate"]')") +
+                    HelpExampleCli("getblockstats", R"(1000 '["minfeerate","avgfeerate"]')") +
+                    HelpExampleRpc("getblockstats", R"("00000000c937983704a73af28acdec37b049d214adbda81d7e2a3dd146f6ed09", ["minfeerate","avgfeerate"])") +
+                    HelpExampleRpc("getblockstats", R"(1000, ["minfeerate","avgfeerate"])")
                 },
     };
     if (request.fHelp || !help.IsValidNumArgs(request.params.size())) {