[document] Fix the doxygen file (#6217)

* [document] Fix the doxygen file

documentation/doxygen/readme.md

@@ -0,0 +1,8 @@
+# How to build doxygen html
+
+1. download from https://doxygen.nl/index.html
+2. open `Doxywizard`
+3. `File` -> `Open`
+4. Open the file ./Doxyfile 
+5.  To tab `Run` , Click `Run doxygen`
+