fix a plural form error in example (#47)

Author: dsonet

src/index.js

@@ -57,7 +57,9 @@ const example1 = {
            *[other] Close {$tabCount} tabs
         }
         tabs-close-warning =
-            You are about to close {$tabCount} tabs.
+            You are about to close {$tabCount ->
+                [one] {$tabCount} tab
+               *[other] {$tabCount} tabs}.
             Are you sure you want to continue?
 
         ## Syncing