Use new comment syntax in Assert

lib/Base/Assert.fram

@@ -1,27 +1,30 @@
-(* This file is part of DBL, released under MIT license.
- * See LICENSE for details.
- *)
+{# This file is part of DBL, released under MIT license.
+ # See LICENSE for details.
+ #}
 
 import open Types
 
-(** Abort the program with given message.
+{## Abort the program with given message.
 
   Note that this function is pure. In correct programs, this function should
-  be never called at runtime, but it can be used to appease the type-checker.
+  never be called at runtime, but it can be used to appease the type-checker.
   Use this function only in impossible match clauses or in case of gross
-  violation of function preconditions (e.g., division by zero). *)
+  violation of function preconditions (e.g., division by zero).
+ #}
 pub let runtimeError {type T} =
   (extern dbl_runtimeError : String ->[] T)
 
-(** Explicitly assert, that this case is impossible *)
+{## Explicitly assert that this case is impossible.
+ #}
 pub let impossible {?msg : String} () =
   runtimeError
     match msg with
     | None     => "Assertion failed"
     | Some msg => msg
     end
 
-(** Assert, that given condition should always hold. *)
+{## Assert that given condition should always hold.
+ #}
 pub let assert {?msg} b =
   if b then ()
   else