Merge bitcoin/bitcoin#25108: tidy: add modernize-use-default-member-init

ac6fbf2c83 tidy: use modernize-use-default-member-init (fanquake)
7aa40f5563 refactor: use C++11 default initializers (fanquake)

Pull request description:

  Refactor and then enable [`modernize-use-default-member-init`](https://clang.llvm.org/extra/clang-tidy/checks/modernize-use-default-member-init.html) in our `clang-tidy` job.

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Tree-SHA512: 536b406f20639f8c588fe9e96175ec60c7bb825506b2670b562370b2f572801c24203c483443be3c199e1b958c0765d4532e57c57a4e78689162a1dd422d844f

src/bitcoin-cli.cpp

@@ -180,10 +180,10 @@ static int AppInitRPC(int argc, char* argv[])
 /** Reply structure for request_done to fill in */
 struct HTTPReply
 {
-    HTTPReply(): status(0), error(-1) {}
+    HTTPReply() = default;
 
-    int status;
-    int error;
+    int status{0};
+    int error{-1};
     std::string body;
 };
 
@@ -244,7 +244,7 @@ static void http_error_cb(enum evhttp_request_error err, void *ctx)
 class BaseRequestHandler
 {
 public:
-    virtual ~BaseRequestHandler() {}
+    virtual ~BaseRequestHandler() = default;
     virtual UniValue PrepareRequest(const std::string& method, const std::vector<std::string>& args) = 0;
     virtual UniValue ProcessReply(const UniValue &batch_in) = 0;
 };