Improve error message when specified scheme is not found (#12182)
Improve error message when specified scheme is not found (#12182)

Since #12027, schemes are read with Xcodeproj rather than parsed from `xcodebuild -list` output. Unlike `xcodebuild -list`, Xcodeproj reads only **shared** schemes (from [project](https://github.com/CocoaPods/Xcodeproj/blob/50e70d32d1176d14c57807c8b5adaa6f42ef38ac/lib/xcodeproj/project.rb#L780-L793)
and also from [workspace](https://github.com/CocoaPods/Xcodeproj/blob/50e70d32d1176d14c57807c8b5adaa6f42ef38ac/lib/xcodeproj/workspace.rb#L199-L204)).

As the specified scheme might exist on the user machine but not be shared, the error message is improved to suggest that the scheme must be shared with a link to Apple's documentation.
daveanderson/fastlane,nafu/fastlane,KrauseFx/fastlane,revile/fastlane,bolom/fastlane,brbulic/fastlane,lacostej/fastlane,nafu/fastlane,kohtenko/fastlane,joshdholtz/fastlane,Econa77/fastlane,brbulic/fastlane,jaleksynas/fastlane,marcelofabri/fastlane,mbogh/fastlane,kazuhidet/fastlane,joshdholtz/fastlane,bassrock/fastlane,lacostej/fastlane,ExtremeMan/fastlane,KrauseFx/fastlane,kazuhidet/fastlane,fastlane/fastlane,icecrystal23/fastlane,kazuhidet/fastlane,farkasseb/fastlane,adamcohenrose/fastlane,mgrebenets/fastlane,tmtrademarked/fastlane,mgrebenets/fastlane,cpk1/fastlane,manuyavuz/fastlane,ashfurrow/fastlane,ashfurrow/fastlane,icecrystal23/fastlane,jaleksynas/fastlane,bassrock/fastlane,fastlane/fastlane,bolom/fastlane,lacostej/fastlane,Econa77/fastlane,lacostej/fastlane,mbogh/fastlane,brbulic/fastlane,ExtremeMan/fastlane,cpk1/fastlane,allewun/fastlane,joshdholtz/fastlane,fastlane/fastlane,brbulic/fastlane,allewun/fastlane,keatongreve/fastlane,taquitos/fastlane,joshdholtz/fastlane,mbogh/fastlane,revile/fastlane,bolom/fastlane,marcelofabri/fastlane,tmtrademarked/fastlane,mbogh/fastlane,keatongreve/fastlane,jaleksynas/fastlane,marcelofabri/fastlane,ExtremeMan/fastlane,ashfurrow/fastlane,marcelofabri/fastlane,brbulic/fastlane,bolom/fastlane,icecrystal23/fastlane,revile/fastlane,nafu/fastlane,keatongreve/fastlane,daveanderson/fastlane,Econa77/fastlane,taquitos/fastlane,mbogh/fastlane,allewun/fastlane,KrauseFx/fastlane,bassrock/fastlane,allewun/fastlane,Econa77/fastlane,lacostej/fastlane,farkasseb/fastlane,ExtremeMan/fastlane,ExtremeMan/fastlane,kazuhidet/fastlane,KrauseFx/fastlane,marcelofabri/fastlane,jaleksynas/fastlane,daveanderson/fastlane,cpk1/fastlane,kohtenko/fastlane,nafu/fastlane,kazuhidet/fastlane,KrauseFx/fastlane,ExtremeMan/fastlane,marcelofabri/fastlane,nafu/fastlane,mbogh/fastlane,Econa77/fastlane,manuyavuz/fastlane,farkasseb/fastlane,adamcohenrose/fastlane,manuyavuz/fastlane,keatongreve/fastlane,revile/fastlane,bassrock/fastlane,keatongreve/fastlane,brbulic/fastlane,jaleksynas/fastlane,tmtrademarked/fastlane,adamcohenrose/fastlane,ashfurrow/fastlane,daveanderson/fastlane,taquitos/fastlane,fastlane/fastlane,farkasseb/fastlane,bassrock/fastlane,daveanderson/fastlane,mgrebenets/fastlane,kazuhidet/fastlane,ashfurrow/fastlane,manuyavuz/fastlane,KrauseFx/fastlane,manuyavuz/fastlane,bolom/fastlane,allewun/fastlane,cpk1/fastlane,lacostej/fastlane,mgrebenets/fastlane,fastlane/fastlane,brbulic/fastlane,keatongreve/fastlane,keatongreve/fastlane,adamcohenrose/fastlane,mgrebenets/fastlane,adamcohenrose/fastlane,Econa77/fastlane,KrauseFx/fastlane,taquitos/fastlane,kazuhidet/fastlane,taquitos/fastlane,farkasseb/fastlane,marcelofabri/fastlane,mbogh/fastlane,adamcohenrose/fastlane,cpk1/fastlane,daveanderson/fastlane,bassrock/fastlane,nafu/fastlane,mgrebenets/fastlane,joshdholtz/fastlane,tmtrademarked/fastlane,farkasseb/fastlane,bolom/fastlane,bolom/fastlane,tmtrademarked/fastlane,tmtrademarked/fastlane,cpk1/fastlane,fastlane/fastlane,taquitos/fastlane,ashfurrow/fastlane,icecrystal23/fastlane,icecrystal23/fastlane,farkasseb/fastlane,manuyavuz/fastlane,jaleksynas/fastlane,mgrebenets/fastlane,nafu/fastlane,ExtremeMan/fastlane,joshdholtz/fastlane,revile/fastlane,daveanderson/fastlane,Econa77/fastlane,tmtrademarked/fastlane,allewun/fastlane,joshdholtz/fastlane,jaleksynas/fastlane,revile/fastlane,icecrystal23/fastlane,taquitos/fastlane,adamcohenrose/fastlane,ashfurrow/fastlane,cpk1/fastlane,allewun/fastlane,revile/fastlane,manuyavuz/fastlane