[fish] Fix intermittent errors on CTRL-T

This seems like a bug of fish, but sometimes when you select an item
fish complains:

"insertion mode switches can not be used when not in insertion mode"

This only happens when using tmux pane. Injecting a dummy command
somehow fixes the issue.

shell/key-bindings.fish

@@ -20,6 +20,7 @@ function fzf_key_bindings
       -o -type d -print \
       -o -type l -print 2> /dev/null | sed 1d | cut -b3-"
     eval "$FZF_CTRL_T_COMMAND | "(__fzfcmd)" -m > $TMPDIR/fzf.result"
+    and sleep 0
     and commandline -i (cat $TMPDIR/fzf.result | __fzf_escape)
     commandline -f repaint
     rm -f $TMPDIR/fzf.result