more docs updates

docs/device/contents.md

@@ -1,6 +1,6 @@
 # micro:bit - the device
 
-The micro:bit device #docs
+The micro:bit device
 
 The micro:bit is a very capable device with many components:
 

docs/device/error-codes.md

@@ -1,6 +1,6 @@
 # Error codes
 
-The micro:bit error codes #docs
+The micro:bit error codes
 
 Your micro:bit may encounter a situation that prevents it from running your code. When this happens, a frowny face will appear on your micro:bit screen (see picture) followed by an error number.
 

docs/device/reactive.md

@@ -1,6 +1,6 @@
 # The micro:bit - a reactive system
 
-The micro:bit is a reactive system. #docs
+The micro:bit is a reactive system.
 
 ### Computing systems