Fix simple typo: drived -> derived (#1646)

Closes #1645
diff --git a/doc/stream.md b/doc/stream.md
index d95de14..04c865c 100644
--- a/doc/stream.md
+++ b/doc/stream.md
@@ -127,7 +127,7 @@
 
 ## IStreamWrapper {#IStreamWrapper}
 
-`IStreamWrapper` wraps any class drived from `std::istream`, such as `std::istringstream`, `std::stringstream`, `std::ifstream`, `std::fstream`, into RapidJSON's input stream.
+`IStreamWrapper` wraps any class derived from `std::istream`, such as `std::istringstream`, `std::stringstream`, `std::ifstream`, `std::fstream`, into RapidJSON's input stream.
 
 ~~~cpp
 #include <rapidjson/document.h>