"add name convention url"

[dzhwinter]

添加了命名规范文档。

另外，new_op_cn.md中OpProtoMaker的示例没有遵守命名规范。

class MulOpMaker : public framework::OpProtoAndCheckerMaker {
 public:
  MulOpMaker(framework::OpProto *proto, framework::OpAttrChecker *op_checker)
      : OpProtoAndCheckerMaker(proto, op_checker) {
    AddInput("X", "The first input of mul op");
    AddInput("Y", "The second input of mul op");
    AddOutput("Out", "The output of mul op");
    AddComment(R"DOC(
Two Element Mul Operator.
The equation is: Out = X * Y
)DOC");
  }
};

其中参数注释有点太粗糙了，没有解释清楚参数。例如"The first input of mul op"没有解释任何事情， 改成 "(Tensor)2D tensor of size (M x K)"会好一些。

Input/Output的注释请尽量包括

1. 参数可以接受的类型
2. 参数的形状
3. 参数的约束，含义解释等等

命名规范中对comments的约束是

• Comments.
  Input/Output/Attr comment follow the format of (type, default value) usage, corresponding to which type it can be and how it will be used by the operator. e.g. Attribute in Accumulator"gamma",(float, default 1.0) Accumulation multiplier.
  Operator comment format of R"DOC(your comment here)DOC". You should explain the input/output of the operator first. If there is math calculation in this operator, you should write the equation in the comment. e.g. Out = X + Y.

命名规范的示例

AddAttr<float>("gamma", "(float, default 1.0) Accumulation multiplier").SetDefault(1.0f);

[wangkuiyi]

LGTM++