fix(docs) typos (#517)

demo/OpenVINO/cpp/README.md

@@ -1,6 +1,6 @@
 # YOLOX-OpenVINO in C++
 
-This toturial includes a C++ demo for OpenVINO, as well as some converted models.
+This tutorial includes a C++ demo for OpenVINO, as well as some converted models.
 
 ### Download OpenVINO models.
 

demo/OpenVINO/python/README.md

@@ -1,6 +1,6 @@
 # YOLOX-OpenVINO in Python
 
-This toturial includes a Python demo for OpenVINO, as well as some converted models.
+This tutorial includes a Python demo for OpenVINO, as well as some converted models.
 
 ### Download OpenVINO models.
 

demo/TensorRT/python/README.md

@@ -1,6 +1,6 @@
 # YOLOX-TensorRT in Python
 
-This toturial includes a Python demo for TensorRT.
+This tutorial includes a Python demo for TensorRT.
 
 ## Install TensorRT Toolkit