[DRE-maint] ruby-thinking-sphinx is marked for autoremoval from testing

[Debian testing autoremoval watch]

ruby-thinking-sphinx 4.1.0-3 is marked for autoremoval from testing on 2020-05-27

It (build-)depends on packages with these RC bugs:
956598: ruby-combustion: ruby-combustion autopkgtest is failing with NoMethodError: undefined method `expect' for #<RSpec::ExampleGroups::CombustionDatabase:0x00005637f96bcec0>