Remove unused unstable feature

Forgot to remove it with e064263f96.

Signed-off-by: pep <pep@bouah.net>

src/main.rs

@@ -14,7 +14,6 @@
 // along with this program. If not, see <https://www.gnu.org/licenses/>.
 
 #![feature(let_chains)]
-#![feature(never_type)]
 
 mod bot;
 mod config;