Fix genscript deprecation version and document reasons for such
Fix genscript deprecation version and document reasons for such

userzimmermann/pytest,ropez/pytest,txomon/pytest,lukas-bednar/pytest,nicoddemus/pytest,hackebrot/pytest,alfredodeza/pytest,ropez/pytest,MengJueM/pytest,pytest-dev/pytest,nicoddemus/pytest,malinoff/pytest,vmalloc/dessert,skylarjhdownes/pytest,tgoodlet/pytest,pfctdayelise/pytest,etataurov/pytest,eli-b/pytest,JonathonSonesen/pytest,jaraco/pytest,Bachmann1234/pytest,RonnyPfannschmidt/pytest,userzimmermann/pytest,markshao/pytest,omarkohl/pytest,tareqalayan/pytest,flub/pytest,vodik/pytest,Bachmann1234/pytest,tomviner/pytest,The-Compiler/pytest,The-Compiler/pytest,JonathonSonesen/pytest,vodik/pytest,davidszotten/pytest,MichaelAquilina/pytest,hpk42/pytest,omarkohl/pytest,hpk42/pytest,Akasurde/pytest,MengJueM/pytest,ddboline/pytest,lukas-bednar/pytest,rmfitzpatrick/pytest,tomviner/pytest