handbook: add readme

Author: zhongsp

doc/handbook/README.md

@@ -0,0 +1,10 @@
+* [基础类型](./Basic Types.md)
+* [接口](./Interfaces.md)
+* [类](./Classes.md)
+* [命名空间和模块](./Modules.md)
+* [函数](./Functions.md)
+* [泛型](./Generics.md)
+* [混入](./Mixins.md)
+* [声明合并](./Declaration Merging.md)
+* [类型推论](./Type Inference.md)
+* [类型兼容性](./Type Compatibility.md)