cabal-install: Add newline at end of 'cabal target --help' output

[tomsmeding]

cabal target seems to be the first cabal-install command that uses a prettyprinter for its --help output. This is all very nice, but you do need to add your own newline if you do so. :)

Template B: This PR does not modify behaviour or interface

• Patches conform to the coding conventions.
• Is this a PR that fixes CI? If so, it will need to be backported to older cabal release branches (ask maintainers for directions).

[ffaf1]

I am not saying this is wrong, but target output is read by other programs. Is there any risk of regressions?

[ulysses4ever]

I checked that other commands' notes have \n's (at least, CmdRun.hs).

[ulysses4ever]

@ffaf1 the updated text is a part of the help message, it seems.

@tomsmeding I just tried cabal target --help and I see even more than one newlines, it seems..

[ulysses4ever]

I've seen discrepancies regarding newlines because of the shell I use (fish). I checked in bash, and, indeed, target's help has one less newline than run's help. So, I assume it's a good change that makes things more uniform.

[tomsmeding]

You do not have to depend on your shell to test this. Use e.g. cabal target --help | xxd to see the actual bytes outputted by cabal; this includes one final 0x0a (i.e. a newline) for cabal run --help, and zero or one (depending on whether this PR is applied) for cabal target --help.

EDIT: Note that your shell prompt may include newlines!

[tomsmeding]

@ulysses4ever Specifically in your case, fish is helpful and prints a ⏎ character if the output of the command did not end in a newline (and then adds its own newline). So rather than showing that there are multiple newlines, your screenshot actually proves that there was none :)