[mlir][docs] Reorder PassWrapper arguments

[marbre]

Summary

Fixes the order of template arguments passed to the PassWrapper.

[mehdi_amini]

Thanks!

mlir/docs/PassManagement.md

 A simple pass may look like:
 
 ```c++
 namespace {
 /// Here we utilize the CRTP `PassWrapper` utility class to provide some
 /// necessary utility hooks. This is only necessary for passes defined directly
 /// in C++. Passes defined declaratively use a cleaner mechanism for providing
 /// these utilities.
-struct MyFunctionPass : public PassWrapper<OperationPass<FuncOp>,
-                                           MyFunctionPass> {
+struct MyFunctionPass : public PassWrapper<MyFunctionPass,
+                                           OperationPass<FuncOp>> {
   void runOnOperation() override {
     // Get the current FuncOp operation being operated on.
     FuncOp f = getOperation();
 
     // Walk the operations within the function.
     f.walk([](Operation *inst) {
       ....
     });

 
 A simple pass may look like:
 
 ```c++
 /// Here we utilize the CRTP `PassWrapper` utility class to provide some
 /// necessary utility hooks. This is only necessary for passes defined directly
 /// in C++. Passes defined declaratively use a cleaner mechanism for providing
 /// these utilities.
-struct MyOperationPass : public PassWrapper<OperationPass<>, MyOperationPass> {
+struct MyOperationPass : public PassWrapper<MyOperationPass, OperationPass<>> {
   void runOnOperation() override {
     // Get the current operation being operated on.
     Operation *op = getOperation();
     ...
   }
 };
 ```