[mlir][vector] add result type to vector.extract assembly format (#66499)

The vector.extract assembly format currently only contains the source
type, for example:

  %1 = vector.extract %0[1] : vector<3x7x8xf32>

it's not immediately obvious if this is the source or result type. This
patch improves the assembly format to make this clearer, so the above
becomes:

  %1 = vector.extract %0[1] : vector<7x8xf32> from vector<3x7x8xf32>