message: Fix BTreeMap documentation
diff: @@ -11,7 +11,7 @@ let hashmap:hmap[] = [ foo=hello bar=world fizz=I buzz=was bazz=here ]
  ## Create a BTreeMap
  ```
  -let hashmap:hmap[] = [ foo=hello bar=world fizz=I buzz=was bazz=here ]
  +let btreemap:bmap[] = [ foo=hello bar=world fizz=I buzz=was bazz=here ]
  ```
  ## Fetch a variables by key
  