fix typo

Fix typo: tradeoff -> trade-off

first-edition/src/release-channels.md

@@ -28,7 +28,7 @@ Generally speaking, unless you have a specific reason, you should be using the
 stable release channel. These releases are intended for a general audience.
 
 However, depending on your interest in Rust, you may choose to use nightly
-instead. The basic tradeoff is this: in the nightly channel, you can use
+instead. The basic trade-off is this: in the nightly channel, you can use
 unstable, new Rust features. However, unstable features are subject to change,
 and so any new nightly release may break your code. If you use the stable
 release, you cannot use experimental features, but the next release of Rust