docs(@angular/cli): Update xi18n outfile argument string

Should be ` --out-file` which is what the cli shows when you use `ng xi18n --help` to list commands

docs/documentation/xi18n.md

@@ -39,7 +39,7 @@
 <details>
   <summary>outfile</summary>
   <p>
-    <code>--outfile</code> (aliases: <code>-of</code>)
+    <code>--out-file</code> (aliases: <code>-of</code>)
   </p>
   <p>
     Name of the file to output.