Update navigation.md (#1252)

The sentence above mentions that the string represents the path. But I think this will be much clearer because not everyone wants to read the text. So it's instantly recognizeable that if you just pass a simple string it's a path and not the route name.

Author: christianmalek

docs/en/essentials/navigation.md

@@ -15,7 +15,7 @@ This is the method called internally when you click a `<router-link>`, so clicki
 The argument can be a string path, or a location descriptor object. Examples:
 
 ``` js
-// literal string
+// literal string path
 router.push('home')
 
 // object