List the gems

docs/RUBY_VERSIONS.md

@@ -36,9 +36,15 @@ what was an already-EOL but still-supported older ruby version.
 
 ## Coordination across gems
 
-We will keep the family of Standard gems -- `standard`, `standard-rails`,
-`standard-performance`, and `standard-custom` -- aligned in regard to:
+We will align versions/dependencies amongst the family of Standard gems:
 
-- The minimum required ruby versions in their `gemspec` settings
-- Using that version in the internal `.standard.yml` configurations
-- The CI ruby matrix of versions that each supports
+- [Standard Ruby](https://github.com/standardrb/standard)
+- [standard-custom](https://github.com/standardrb/standard-custom)
+- [standard-performance](https://github.com/standardrb/standard-performance)
+- [standard-rails](https://github.com/standardrb/standard-rails)
+
+This means keeping them consistent in regard to:
+
+- The minimum required ruby version configured in their `gemspec`
+- Using that version in their internal `.standard.yml` configurations
+- Including the full range of supported rubies in their CI ruby matrix