update layout map examples in doc, drop stale ones

- add more examples for affine layout maps showing various use
  cases

- affine map range sizes were removed from code, but examples in
  LangRef weren't updated

Signed-off-by: Uday Bondhugula <uday@polymagelabs.com>

Closes tensorflow/mlir#142

COPYBARA_INTEGRATE_REVIEW=https://github.com/tensorflow/mlir/pull/142 from bondhugula:doc 3291a8784bc69883f7a7cead21445fc8118aaad2
PiperOrigin-RevId: 270548991