[mlir][sparse] Update examples in Ops.td (llvm#69499)

Example:

dimLevelType = [ "compressed", "compressed" ] to
map = (d0, d1) -> (d0 : compressed, d1 : compressed)

Author: yinying-lisa-li

mlir/include/mlir/Dialect/SparseTensor/IR/SparseTensorOps.td

@@ -446,10 +446,13 @@ def SparseTensor_StorageSpecifierInitOp : SparseTensor_Op<"storage_specifier.ini
     Example:
 
     ```mlir
-    #CSR = #sparse_tensor.encoding<{ dimLevelType = [ "dense", "compressed" ]}>
+    #CSR = #sparse_tensor.encoding<{
+      map = (i, j) -> (i : dense, j : compressed)
+    }>
     #CSR_SLICE = #sparse_tensor.encoding<{
-      dimLevelType = [ "dense", "compressed" ],
-      slice = [ (1, 4, 1), (1, 4, 2) ]
+      map = (d0 : #sparse_tensor<slice(1, 4, 1)>,
+             d1 : #sparse_tensor<slice(1, 4, 2)>) ->
+            (d0 : dense, d1 : compressed)
     }>
 
     %0 = sparse_tensor.storage_specifier.init :  !sparse_tensor.storage_specifier<#CSR>
@@ -1260,8 +1263,7 @@ def SparseTensor_ForeachOp : SparseTensor_Op<"foreach",
      For example:
      ```mlir
      #COL_MAJOR = #sparse_tensor.encoding<{
-       dimLevelType = [ "compressed", "compressed" ],
-       dimOrdering = affine_map<(i,j) -> (j,i)>
+       map = (d0, d1) -> (d1 : compressed, d0 : compressed)
      }>
 
      // foreach on a column-major sparse tensor
@@ -1271,7 +1273,7 @@ def SparseTensor_ForeachOp : SparseTensor_Op<"foreach",
      }
 
      #ROW_MAJOR = #sparse_tensor.encoding<{
-       dimLevelType = [ "compressed", "compressed" ],
+       map = (d0, d1) -> (d0 : compressed, d1 : compressed)
      }>
 
      // foreach on a row-major sparse tensor