Fix proof coherent modules form abelian cat

Thanks to JuanPablo
http://stacks.math.columbia.edu/tag/01BY#comment-977
Slogan by Johan + Johan

It seems like you get a better slogan if you think geometrically.
http://stacks.math.columbia.edu/tag/00SM#comment-980
Slogan by Johan Commelin
http://stacks.math.columbia.edu/tag/002P#comment-981
Slogan by Johan Commelin
http://stacks.math.columbia.edu/tag/00WT#comment-982
Slogan by Johan + Johan
http://stacks.math.columbia.edu/tag/051S#comment-983
Slogan by Johan Commelin
http://stacks.math.columbia.edu/tag/04K0#comment-984
Slogan by Johan Commelin
http://stacks.math.columbia.edu/tag/025Q#comment-985
Slogan by Johan Commelin
http://stacks.math.columbia.edu/tag/0A4E#comment-986
Slogan by Johan + Johan
http://stacks.math.columbia.edu/tag/05RJ#comment-987
Slogan by Johan and Johan
http://stacks.math.columbia.edu/tag/0A03#comment-988
Slogan and typo by Johan Commelin
http://stacks.math.columbia.edu/tag/019Y#comment-989
http://stacks.math.columbia.edu/tag/019Y#comment-990
Slogan by Johan Commelin
http://stacks.math.columbia.edu/tag/02Y2#comment-991