Typo in algebra.tex

Thanks to OlgaD
http://stacks.math.columbia.edu/tag/00DY#comment-1143
Add slogan and improve sentence in properties.tex

Thanks to Simon Pepin Lehalleur and Pieter Belmans
http://stacks.math.columbia.edu/tag/01P7#comment-1144
http://stacks.math.columbia.edu/tag/01P7#comment-1145
Typo in algebra.tex

Thanks to OlgaD
http://stacks.math.columbia.edu/tag/00EB#comment-1146
Typo in topology.tex

Thanks to sid
http://stacks.math.columbia.edu/tag/004Z#comment-1147
Fix lemma in stacks-perfect.tex

Thanks to Olaf Sdchn\"urer
http://stacks.math.columbia.edu/tag/07B9#comment-1148
Typo in algebra.tex

Thanks to Matthieu Romagny
http://stacks.math.columbia.edu/tag/04EA#comment-1149
Add missing arrows in sites-modules.tex

Thanks to Olaf Schn\"urer
http://stacks.math.columbia.edu/tag/03DE#comment-1151
Typo in algebra.tex

Thanks to Yu Zhao
http://stacks.math.columbia.edu/tag/00L9#comment-1152
Add John Yu and Yifei Zhao to CONTRIBUTORS

They wrote the material in Tag 09P5, see commit

4b1f9eaa56375a6ce8a5c09378821c8294f76339
Fix typo in spaces-pushouts.tex

Thanks to Matthieu Romagny
http://stacks.math.columbia.edu/tag/0AGF#comment-1155
http://stacks.math.columbia.edu/tag/0AGF#comment-1156
Use degenerate not converge

Thanks to Pieter Belmans
http://stacks.math.columbia.edu/tag/01F4#comment-1159
Fix typo in more-algebra.tex

Thanks to Matthieu Romagny
http://stacks.math.columbia.edu/tag/0656#comment-1160
Error in statement lemma and proof in topology.tex

Need to say "closed in constructible topology"

Thanks to Zhang
http://stacks.math.columbia.edu/tag/09XW#comment-1161
Fix typo in morphisms.tex

Thanks to prefaisceau
http://stacks.math.columbia.edu/tag/01VW#comment-1162
Fix typo in algebra.tex

Thanks to Hu Fei
http://stacks.math.columbia.edu/tag/031Q#comment-1164