Fix typos in manual for speex_preprocess API
Fix typos in manual for speex_preprocess API

mwgoldsmith/speex,mwgoldsmith/speex,felipebetancur/speex,felipebetancur/speex,ksophocleous/speex,lowlevel-studios/speex-android,lowlevel-studios/speex-android,ksophocleous/speex,lowlevel-studios/speex-android,mwgoldsmith/speex,mwgoldsmith/speex,lu-zero/speex,ksophocleous/speex,lu-zero/speex,lu-zero/speex,felipebetancur/speex,felipebetancur/speex