fix readme.md for handwired

keyboards/handwired/bstk100/readme.md

@@ -15,15 +15,15 @@ see [[FREE WING HOME PAGE]](http://www.neko.ne.jp/~freewing/) for more detail .
 
 Make example for this keyboard (after setting up your build environment):
 
-    make bstk100:default
+    make handwired/bstk100:default
 
 Enable VIA feature in QMK
 
-    make bstk100:via
+    make handwired/bstk100:via
 
 Flashing example for this keyboard:
 
-    make bstk100:default:flash
+    make handwired/bstk100:default:flash
 
 See the [build environment setup](https://docs.qmk.fm/#/getting_started_build_tools) and the [make instructions](https://docs.qmk.fm/#/getting_started_make_guide) for more information. Brand new to QMK? Start with our [Complete Newbs Guide](https://docs.qmk.fm/#/newbs).