Incorrect classification for stft.json and stft_real.json

[andyx13]

The stft and stft_real methods are listed in the JSON annotations under sigpro.transformations.frequency.stft.stft andsigpro.transformations.frequency.stft.stft_real, respectively. However, these primitives are actually implemented in the correct locations sigpro.transformations.frequency_time.stft.stft and sigpro.transformations.frequency_time.stft.stft_real. The JSON annotation should be amended to reflect this.