sway: add bind for pcmanfm and switch to alacritty for now

config/etc/sway/config.nix

@@ -52,7 +52,7 @@ in pkgs.writeText "config"
   set $up k
   set $right l
   # Your preferred terminal emulator
-  set $term ${pkgs.wezterm}/bin/wezterm
+  set $term ${pkgs.alacritty}/bin/alacritty
   # Your preferred application launcher
   # Note: it's recommended that you pass the final command to sway
   set $menu ${pkgs.rofi-wayland}/bin/rofi -config /etc/rofi.rasi -show combi
@@ -97,6 +97,7 @@ in pkgs.writeText "config"
   #
   # start a terminal
   bindsym $mod+Return exec $term
+  bindsym $mod+o exec ${pkgs.pcmanfm}/bin/pcmanfm
 
   # kill focused window
   bindsym $mod+Shift+q kill