[mlir] Add base class type aliases for rewrites/conversions. NFC. (#158433)

This is to simplify writing rewrite/conversion patterns that usually
start with:
```c++
struct MyPattern : public OpRewritePattern<MyOp> {
  using OpRewritePattern::OpRewritePattern;
```

and allow for:
```c++
struct MyPattern : public OpRewritePattern<MyOp> {
  using Base::Base;
```

similar to how we enable it for pass classes.

GitOrigin-RevId: c88f3c582dc2ef5f2fdfd0c5887f5f7562f49095
3 files changed
tree: d67a41bde04ffd5d1a5b2f33df66d85f87630ffd
  1. benchmark/
  2. cmake/
  3. docs/
  4. examples/
  5. include/
  6. lib/
  7. python/
  8. test/
  9. tools/
  10. unittests/
  11. utils/
  12. .clang-format
  13. .clang-tidy
  14. CMakeLists.txt
  15. LICENSE.TXT
  16. Maintainers.md
  17. README.md
README.md

Multi-Level Intermediate Representation

See https://mlir.llvm.org/ for more information.