Update instructions.

2021.On the Correctness of Monadic Backward Induction/code/README.md

@@ -39,11 +39,11 @@ The following has been successfully tested using Idris version 1.3.2:
 
 * The source files can be typechecked all at once with
 
-  `idris --checkpkg valval.ipkg`
+  `idris --checkpkg code.ipkg`
 
   or built with
 
-  `idris --build valval.ipkg`
+  `idris --build code.ipkg`
 
 * Individual files can be loaded into the Idris REPL using
 
@@ -51,7 +51,7 @@ The following has been successfully tested using Idris version 1.3.2:
 
 * Generated intermediate code and executables can be deleted with
 
-  `idris --clean valval.ipkg`
+  `idris --clean code.ipkg`
 
 
 ## References