Actually return the strategy

lib/linguist/language.rb

@@ -108,9 +108,10 @@ module Linguist
       Linguist.instrument("linguist.detection", :blob => blob) do
         # Call each strategy until one candidate is returned.
         languages = []
-        strategy = nil
+        returning_strategy = nil
 
         STRATEGIES.each do |strategy|
+          returning_strategy = strategy
           candidates = Linguist.instrument("linguist.strategy", :blob => blob, :strategy => strategy, :candidates => languages) do
             strategy.call(blob, languages)
           end
@@ -125,7 +126,7 @@ module Linguist
           end
         end
 
-        Linguist.instrument("linguist.detected", :blob => blob, :strategy => strategy, :language => languages.first)
+        Linguist.instrument("linguist.detected", :blob => blob, :strategy => returning_strategy, :language => languages.first)
 
         languages.first
       end

test/test_instrumentation.rb

@@ -38,7 +38,13 @@ class TestInstrumentation < Minitest::Test
     blob = fixture_blob("Data/Modelines/ruby")
     Language.detect(blob)
 
+    detect_event = Linguist.instrumenter.events.last
+    detect_event_payload = detect_event[:args].first
+
     assert_equal 3, Linguist.instrumenter.events.size
-    assert_equal "linguist.detected", Linguist.instrumenter.events.last.name
+    assert_equal "linguist.detected", detect_event.name
+    assert_equal Language['Ruby'], detect_event_payload[:language]
+    assert_equal blob, detect_event_payload[:blob]
+    assert_equal Linguist::Strategy::Modeline, detect_event_payload[:strategy]
   end
 end