Fixity mangler isn't complete

[nibro]

The fixity mangler fails to handle all cases:

main = forM_ cmdReports $ \x -> do
               putStrLn $ "Writing report to " ++ x ++ " ..."
               writeReport x ideas

Here, the insides of the lambda are not mangled, leaving the default left-associative order for the second line operators.

[nibro]

I missed the right sub-branch of infix expressions in some cases. Fixed now, case closed.