[mlir][vector][NFC] Update `vector.flat_transpose` description

[kuhar]

Summary

Change the example to match how this op is actually printed. Do not use
'smart quotes' in the description.

mlir/include/mlir/Dialect/Vector/IR/VectorOps.td

def Vector_FlatTransposeOp : Vector_Op<"flat_transpose", [Pure,
   let description = [{
     This is the counterpart of llvm.matrix.transpose in MLIR. It serves
     the purposes of more progressive lowering and localized type conversion.
     Higher levels typically lower matrix tranpositions into 'vector.transpose'
     operations. Subsequent rewriting rule progressively lower these operations
     into 'vector.flat_transpose' operations to bring the operations closer
     to the hardware ISA.
 
-    The ‘vector.flat_transpose’ op treats the 1-D input `matrix` as
+    The `vector.flat_transpose` op treats the 1-D input `matrix` as
     a 2-D matrix with <rows> rows and <columns> columns, and returns the
     transposed matrix in flattened form in 'res'.
 
     Also see:
 
     http://llvm.org/docs/LangRef.html#llvm-matrix-transpose-intrinsic
 
     Example:
 
     ```mlir
-    %1 = vector.flat_transpose %0 { rows = 4: i32, columns = 4: i32 }
-       : (vector<16xf32>) -> vector<16xf32>
+    %1 = vector.flat_transpose %0 {columns = 4 : i32, rows = 4 : i32}
+       : vector<16xf32> -> vector<16xf32>
     ```
   }];
   let assemblyFormat = "$matrix attr-dict `:` type($matrix) `->` type($res)";
 }
 
 //===----------------------------------------------------------------------===//
 // SplatOp
 //===----------------------------------------------------------------------===//