Fix outdated command line in docs

eregon · eregon · commit 26e7db7d7a2d · 2019-12-02T16:56:07.000+01:00
diff --git a/doc/contributor/native-image.md b/doc/contributor/native-image.md
@@ -93,7 +93,7 @@ You can build a native build of TruffleRuby using the Native Image Tool from a
 source distribution using:
 
 ```bash
-$ jt build native
+$ jt build --env native
 ```
 
 The disadvantages of the Native Image version of TruffleRuby are:
