message: Add summary and description for HLO EinsumOp and UnaryEinsumOp
diff: @@ -801,7 +801,9 @@ def HLO_DotGeneralOp: HLO_Op<"dot_general", [NoSideEffect]>, BASE_HLO_DotGeneral
  let results = (outs HLO_Tensor);
  }
  -def BASE_EinsumOp {
  +// Define Base Einsum op within the HLO dialect as these are client ops and
  +// therefore this class is not common between HLO and LHLO ops.
  +class BASE_EinsumOp {
  string summary = "Einsum operator";
  string description = [{
  @@ -810,7 +812,7 @@ def BASE_EinsumOp {
  }];
  }
  -def HLO_EinsumOp: HLO_Op<"einsum", [NoSideEffect]> {
  +def HLO_EinsumOp: HLO_Op<"einsum", [NoSideEffect]>, BASE_EinsumOp {
  let arguments = (ins
  HLO_Tensor:$lhs,
  HLO_Tensor:$rhs,
  @@ -823,7 +825,7 @@ def HLO_EinsumOp: HLO_Op<"einsum", [NoSideEffect]> {
  // side HLO ops.
  }
  -def HLO_UnaryEinsumOp: HLO_Op<"unary_einsum", [NoSideEffect]> {
  +def HLO_UnaryEinsumOp: HLO_Op<"unary_einsum", [NoSideEffect]>, BASE_EinsumOp {
  let arguments = (ins
  HLO_Tensor:$operand,
  StrAttr:$einsum_config
  