Add StatusCode enum (#1739)

* Add StatusCode enum

* Remove changes on RFC 9110

* Add number suffixes to StatusCode constants

* Remove docs for StatusCode constants

httplib.h

@@ -1791,6 +1791,81 @@ inline void default_socket_options(socket_t sock) {
 #endif
 }
 
+enum StatusCode {
+  // Information responses
+  Continue_100 = 100,
+  SwitchingProtocol_101 = 101,
+  Processing_102 = 102,
+  EarlyHints_103 = 103,
+
+  // Successful responses
+  OK_200 = 200,
+  Created_201 = 201,
+  Accepted_202 = 202,
+  NonAuthoritativeInformation_203 = 203,
+  NoContent_204 = 204,
+  ResetContent_205 = 205,
+  PartialContent_206 = 206,
+  MultiStatus_207 = 207,
+  AlreadyReported_208 = 208,
+  IMUsed_226 = 226,
+
+  // Redirection messages
+  MultipleChoices_300 = 300,
+  MovedPermanently_301 = 301,
+  Found_302 = 302,
+  SeeOther_303 = 303,
+  NotModified_304 = 304,
+  UseProxy_305 = 305,
+  unused_306 = 306,
+  TemporaryRedirect_307 = 307,
+  PermanentRedirect_308 = 308,
+
+  // Client error responses
+  BadRequest_400 = 400,
+  Unauthorized_401 = 401,
+  PaymentRequired_402 = 402,
+  Forbidden_403 = 403,
+  NotFound_404 = 404,
+  MethodNotAllowed_405 = 405,
+  NotAcceptable_406 = 406,
+  ProxyAuthenticationRequired_407 = 407,
+  RequestTimeout_408 = 408,
+  Conflict_409 = 409,
+  Gone_410 = 410,
+  LengthRequired_411 = 411,
+  PreconditionFailed_412 = 412,
+  PayloadTooLarge_413 = 413,
+  UriTooLong_414 = 414,
+  UnsupportedMediaType_415 = 415,
+  RangeNotSatisfiable_416 = 416,
+  ExpectationFailed_417 = 417,
+  ImATeapot_418 = 418,
+  MisdirectedRequest_421 = 421,
+  UnprocessableContent_422 = 422,
+  Locked_423 = 423,
+  FailedDependency_424 = 424,
+  TooEarly_425 = 425,
+  UpgradeRequired_426 = 426,
+  PreconditionRequired_428 = 428,
+  TooManyRequests_429 = 429,
+  RequestHeaderFieldsTooLarge_431 = 431,
+  UnavailableForLegalReasons_451 = 451,
+
+  // Server error responses
+  InternalServerError_500 = 500,
+  NotImplemented_501 = 501,
+  BadGateway_502 = 502,
+  ServiceUnavailable_503 = 503,
+  GatewayTimeout_504 = 504,
+  HttpVersionNotSupported_505 = 505,
+  VariantAlsoNegotiates_506 = 506,
+  InsufficientStorage_507 = 507,
+  LoopDetected_508 = 508,
+  NotExtended_510 = 510,
+  NetworkAuthenticationRequired_511 = 511,
+};
+
 inline const char *status_message(int status) {
   switch (status) {
   case 100: return "Continue";