[QOL] Search Schematic (#2089)

* autofocus implementation

* enter to select first schematic implementation

* fix undeclared variable

* fix import

core/src/mindustry/input/DesktopInput.java

@@ -386,6 +386,7 @@ public class DesktopInput extends InputHandler{
                 ui.schematics.hide();
             }else{
                 ui.schematics.show();
+                ui.schematics.focusSearchField();
             }
         }