add duckduckgo cli to configuration for terminal search

middle mouse emulation to me with a perfectly functioning and blossoming
middle mouse button is merely a distraction at best, while gaming it
was crippling for a long time before I realised that it was not my mouse
being broken or me being stupid, but rather this setting being enabled
by default for some spirit-forsaken reason .  fuck this . it still gets
enabled by default, so it doesn't even help ?  aaargh

nix/configuration.nix

@@ -97,6 +97,7 @@
     alacritty
     asciidoctor-with-extensions
     bat
+    ddgr
     dunst
     eww
     feh
@@ -220,6 +221,12 @@
 
   		desktopManager.runXdgAutostartIfNone = true;
       displayManager.startx.enable = true;
+
+      libinput = {
+        enable = true;
+        middleEmulation = false;
+      };
+
       windowManager.leftwm.enable = true;
       xkb.layout = "us";
       xkb.variant = "dvp";