docs(component-styles): mark `__moduleName` experimental; use alert instead of callout.

closes #1054

public/docs/ts/latest/guide/component-styles.jade

@@ -118,7 +118,7 @@ a(id="special-selectors")
 :marked
   The `/deep/` selector also has the alias `>>>`. We can use either of the two interchangeably.
 
-.callout.is-important
+.alert.is-important
   :marked
     The `/deep/` and `>>>` selectors should only be used with **emulated** view encapsulation.
     This is the default and it is what we use most of the time. See the
@@ -160,7 +160,7 @@ a(id='loading-styles')
   
 +makeExample('component-styles/ts/app/hero-details.component.ts', 'styleurls')
   
-.callout.is-important
+.alert.is-important
   :marked
     The URL is ***relative to the application root*** which is usually the
     location of the `index.html` web page that hosts the application. 
@@ -333,6 +333,10 @@ code-example(format='').
 
   Fortunately, *certain* module loaders make it easy.
   SystemJS (starting in v.0.19.19) sets a special `__moduleName` variable to the URL of the component file.
+.alert.is-important
+  :marked
+    Caution: we currently regard the *__moduleName* feature as experimental.
+:marked
   Now it's trivial to set the `moduleId` to the `__moduleName` and write module-relative paths for style and template URLs.
   
 +makeExample('component-styles/ts/app/quest-summary.component.ts','', 'app/quest-summary.component.ts')