Slight code style change upon @ioquatix's suggestion.

Author: mtortonesi

lib/truffle/coverage.rb

@@ -18,7 +18,7 @@ def self.supported?(mode)
   def self.start(*arguments, **options)
     # We have to track if the :lines option was provided, as that calls for a
     # different result format
-    @lines = true if options[:lines]
+    @lines = !!options[:lines]
     Truffle::Coverage.enable
   end