[MLIR][Linalg] Fixed obsolete examples in the MLIR Linalg Dialect doc
This diff fixes some obsolete examples in the Linalg dialect documentation: https://mlir.llvm.org/docs/Dialects/Linalg/
These examples are used to explain the basic properties of the Linalg dialect, which are not automatically generated from TableGen and are using out-of-date MLIR/Linalg syntax.
This diff extends each example by adding essential attributes and changing its syntax to make it processible by mlir-opt. There is also a command attached to each example that says how the example can be processed.
Reviewed By: ftynse
Differential Revision: https://reviews.llvm.org/D84229