Corrected wording in the Desktop section

Bullet #3 was referencing "Android".

CONTRIBUTING.md

diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index b8a0018..e24946f 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -87,7 +87,7 @@
 
  * `gclient sync` to update your dependencies.
  * `./sky/tools/gn` to prepare your build files.
- * `ninja -C out/Debug` to build an Android Debug binary.
+ * `ninja -C out/Debug` to build a desktop Debug binary.
 
 To run the tests: