Improve error messages (#75)

* Improve error messages

* Regenerate examples

Author: VojtechVitek

_examples/golang-basics/example.gen.go

@@ -54,14 +54,14 @@ func (s *{{$serviceName}}) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		handler = s.serve{{$method.Name | firstLetterToUpper}}JSON{{if $method.StreamOutput}}Stream{{end}}
 	{{- end}}
 	default:
-		err := ErrWebrpcBadRoute.WithCausef("no WebRPC method defined for path %v", r.URL.Path)
+		err := ErrWebrpcBadRoute.WithCausef("no webrpc method defined for path %v", r.URL.Path)
 		s.sendErrorJSON(w, r, err)
 		return
 	}
 
 	if r.Method != "POST" {
 		w.Header().Add("Allow", "POST") // RFC 9110.
-		err := ErrWebrpcBadMethod.WithCausef("unsupported method %v (only POST is allowed)", r.Method)
+		err := ErrWebrpcBadMethod.WithCausef("unsupported HTTP method %v (only POST is allowed)", r.Method)
 		s.sendErrorJSON(w, r, err)
 		return
 	}