Add missing comments

internal/server/srverrors/error.go

@@ -5,10 +5,13 @@ import (
 	"net/http"
 )
 
+// A ServerErrMessage represents the reason why the error happened
 type ServerErrMessage struct {
 	Reason string `json:"reason"`
 }
 
+// WriteErrorResponse writes the error JSON body to the provided http.ResponseWriter,
+// after setting the appropiate Content-Type header
 func WriteErrorResponse(statusCode int, reasonMsg string, res http.ResponseWriter) {
 	respBody := ServerErrMessage{}
 	respBody.Reason = reasonMsg