Clarify documentation on readProcess regarding interactivity

In [a Reddit thread](https://www.reddit.com/r/haskell/comments/byy4wh/readprocess_strict_output_and_interactive_use/) a user was confused by the comment on `readProcess` "Output is returned strictly, so this is not suitable for interactive applications". They assumed that it mean that `readProcess` should not be used when implementing an interactive application, whereas it (presumably) means that it should not be used to run processes that interact over the standard file streams.

Perhaps the comment could be changed to "Output is returned strictly, so this is not suitable for running processes that interact over the standard file streams." or something similarly clarifying.