[Cin] Cinelerra-GG_Manual. A stupid thing. FFMEG instead of FFMPEG

In the Manual_20220228.pdf there are stupid errors at the pages 167 and 168 because I wrote wrong in the CinelerraGG Forum https://www.cinelerra-gg.org/forum/help-video/how-to-optimize-playback/?orde... It should be "Rescaled to project size (*FFMPEG* only) = unchecked" instead of "Rescaled to project size (*FFMEG* only) = unchecked". Sorry for my mistake. IgorBeg