Instancer : Fix ContextVariablePlug description
Instancer : Fix ContextVariablePlug description

GafferHQ/gaffer,andrewkaufman/gaffer,johnhaddon/gaffer,andrewkaufman/gaffer,GafferHQ/gaffer,GafferHQ/gaffer,johnhaddon/gaffer,hradec/gaffer,hradec/gaffer,johnhaddon/gaffer,andrewkaufman/gaffer,andrewkaufman/gaffer,johnhaddon/gaffer,GafferHQ/gaffer,GafferHQ/gaffer,andrewkaufman/gaffer,hradec/gaffer,hradec/gaffer,hradec/gaffer,johnhaddon/gaffer