fix fly_machine.md typo (#1935)

Co-authored-by: Didier Catz <[email protected]>

Author: didier

flyctl/cmd/fly_machine.md

@@ -1,6 +1,5 @@
 Manage Fly Machines. Fly Machines are super-fast, lightweight VMs that can be created,
-and then quickly started and stopped as needed with flyctl commands or with the
-Machines REST fly.
+and then quickly started and stopped as needed with flyctl commands or with the Machines REST API.
 
 ## Usage
 ~~~