[mlir] Makes `zip_shortest` an optional keyword in `transform.foreach` (#98492)
This PR addresses a [comment] made by @ftynse about the syntax for
`ForeachOp`. The syntax was modified by @muneebkhan85 in #82792, where
the attribute dictionary was moved to the middle.
This patch moves it back to its original place at the end. And
introduces an optional keyword for `zip_shortest`.
[comment]:
https://github.com/llvm/llvm-project/pull/82792#pullrequestreview-2132814144