[Intl] Improve note about ext-intl.

Author: enumag

components/intl.rst

@@ -11,7 +11,9 @@ The Intl Component
 .. caution::
 
     The replacement layer is limited to the locale "en". If you want to use
-    other locales, you should `install the intl extension`_ instead.
+    other locales, you should `install the intl extension`_. There is no conflict 
+    between the two though. Even if you use the extension this package can still
+    be useful to access the ICU data.
 
 .. seealso::