fix CUDA wrapping

[nniclausse]

When trying to use SHTns with CUDA, i got the following error :

ERROR: LoadError: UndefVarError: `cu_SHqst_to_spat` not defined in `SHTnsCUDAExt`
Suggestion: check for spelling errors or missing imports.
Stacktrace:
 [1] synth!(cfg::SHTns.SHTnsCfg{Real, SHTns.Orthonormal, SHTns.QuickInit}, qlm::CuArray{ComplexF64, 1, CUDA.DeviceMemory}, slm::CuArray{ComplexF64, 1, CUDA.DeviceMemory}, tlm::CuArray{ComplexF64, 1, CUDA.DeviceMemory}, ur::CuArray{Float64, 2, CUDA.DeviceMemory}, utheta::CuArray{Float64, 2, CUDA.DeviceMemory}, uphi::CuArray{Float64, 2, CUDA.DeviceMemory})
   @ SHTnsCUDAExt ~/.julia/packages/SHTns/g4u8S/ext/SHTnsCUDAExt/synth.jl:60
 [2] synth(cfg::SHTns.SHTnsCfg{Real, SHTns.Orthonormal, SHTns.QuickInit}, qlm::CuArray{ComplexF64, 1, CUDA.DeviceMemory}, slm::CuArray{ComplexF64, 1, CUDA.DeviceMemory}, tlm::CuArray{ComplexF64, 1, CUDA.DeviceMemory})
   @ SHTnsCUDAExt ~/.julia/packages/SHTns/g4u8S/ext/SHTnsCUDAExt/synth.jl:41

the fix is to add a missing "cu_" in two method name

[codecov]

Codecov Report

❌ Patch coverage is 0% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 45.58%. Comparing base (ce0285e) to head (2eaf9f5).
⚠️ Report is 2 commits behind head on master.

Files with missing lines	Patch %	Lines
ext/SHTnsCUDAExt/sht.jl	0.00%	2 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##           master      #12   +/-   ##
=======================================
  Coverage   45.58%   45.58%           
=======================================
  Files           9        9           
  Lines         430      430           
=======================================
  Hits          196      196           
  Misses        234      234           

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[fgerick]

Thank you!