Fix silent yank error on macOS

My `$tmux_yank_copy_command` is `reattach-to-user-namespace pbcopy`.
Running it myself in `nohup` is fine. However, tmux-fingers running it
with `nohup` produces a silent error: `nohup: can't detach from console:
Inappropriate ioctl for device`. Removing `nohup` restores my yank
ability.

scripts/fingers.sh

@@ -103,7 +103,7 @@ function copy_result() {
   fi
 
   if [[ $HAS_TMUX_YANK = 1 ]]; then
-    echo -n "$result" | eval "nohup $tmux_yank_copy_command" > /dev/null
+    echo -n "$result" | eval "$tmux_yank_copy_command" > /dev/null
   fi
 }