open: improve page (#1437)

* Wrap osascript within backticks

pages/osx/open.md

@@ -8,7 +8,11 @@
 
 - Run a graphical macOS application:
 
-`open /Applications/{{Application.app}}`
+`open -a {{Application}}`
+
+- Run a graphical macOS app based on the bundle identifier (refer to `osascript` for an easy way get this):
+
+`open -b {{com.domain.application}}`
 
 - Open the current directory in Finder: