fix examples for qudits interface

[Xiu-zhe (Roger) Luo]

currently our doc build is failing

ERROR: LoadError: LoadError: MethodError: no method matching nqudits(::Main.##293.QFT{3})
Closest candidates are:
  nqudits(!Matched::RotationGate) at ~/work/Yao.jl/Yao.jl/lib/YaoBlocks/src/primitive/rotation_gate.jl:30
  nqudits(!Matched::GeneralMatrixBlock) at ~/work/Yao.jl/Yao.jl/lib/YaoBlocks/src/primitive/general_matrix_gate.jl:22
  nqudits(!Matched::Add) at ~/work/Yao.jl/Yao.jl/lib/YaoBlocks/src/composite/reduce.jl:[19](https://github.com/QuantumBFS/Yao.jl/runs/5549314240?check_suite_focus=true#step:6:19)
  ...
in expression starting at string:2
when executing the following code block in file `~/work/Yao.jl/Yao.jl/docs/src/quick-start/2.qft-phase-estimation/main.jl`

[Jinguo Liu]

Fixed in the master.