improve formatting in stopwatch.rst

Author: SimonHeimberg

components/stopwatch.rst

@@ -30,7 +30,7 @@ microtime by yourself. Instead, use the simple
     $stopwatch = new Stopwatch();
     // starts event named 'eventName'
     $stopwatch->start('eventName');
-    // ... some code goes here
+:    // ... some code goes here
     $event = $stopwatch->stop('eventName');
 
 The :class:`Symfony\\Component\\Stopwatch\\StopwatchEvent` object can be retrieved
@@ -51,13 +51,12 @@ Symfony Profiler tool uses categories to nicely color-code different events.
 Usage in symfony
 ----------------
 
-In a Controller, do:
+In a Controller, do::
 
     $stopwatch = $this->get('debug.stopwatch');
     $stopwatch->start('anEvent');
 
-Or inject `Symfony\Component\Stopwatch\Stopwatch` by autowiring.
-
+Or inject :class:`Symfony\\Component\\Stopwatch\\Stopwatch` by autowiring.
 Thereafter this timing can be seen in the profiler.
 
 Periods