Set DocumentationBaseURL and DocumentationExtension

This allows `ruby-lsp` to link to cop documentation for this extension.

Documentation here is in markdown and rubocop didn't support that until
recently, so only set this when it supports both options.
Otherwise it would link to non-existant html docs.

lib/rubocop/sorbet/inject.rb

@@ -11,6 +11,14 @@ class << self
         def defaults!
           path = CONFIG_DEFAULT.to_s
           hash = ConfigLoader.send(:load_yaml_configuration, path)
+          if Gem::Version.new(RuboCop::Version::STRING) >= Gem::Version.new("1.66")
+            # We use markdown for cop documentation. Unconditionally setting
+            # the base url will produce incorrect urls on older RuboCop versions,
+            # so we do that for fully supported version only here.
+            hash["Sorbet"] ||= {}
+            hash["Sorbet"]["DocumentationBaseURL"] = "https://github.com/Shopify/rubocop-sorbet/blob/main/manual"
+            hash["Sorbet"]["DocumentationExtension"] = ".md"
+          end
           config = Config.new(hash, path).tap(&:make_excludes_absolute)
           puts "configuration from #{path}" if ConfigLoader.debug?
           config = ConfigLoader.merge_with_default(config, path)