libgetopts: use Result<Match, _Fail> instead of Result alias for getopts return type

[jxs]

getopts::getopts doc shows Result as the return type, which can be confusing, due the aliased Result to Result<Match, _Fail>

[lilyball]

What's the motivation for this change?

[jxs]

sorry, forgot to add description.
The motivation for that pr was to make the method more explicit.
But I only noticed now, across std doc seems to be both the aliased Result and Result<U, T>
maybe this should be pondered and discussed, to see which makes more sense, and make it uniform across std doc

[lilyball]

We also use a Result typedef in std::fmt. If you feel that using a Result typedef here is confusing because std::result::Result is in the prelude, then you should file an issue about it and try to come up with a general solution.

Offhand, we could perhaps have rustdoc detect when a type shadows something in the prelude and adjust instances of that shadowing type to include the module name, e.g. fmt::Result instead of Result.

Incidentally, if you look at the std::fmt documentation right now you'll actually see Result<(), FormatError> instead of Result. This is a bug, rustdoc is inlining type definitions in some cases. If the bug is fixed it would display Result just like getopts does.

[jxs]

I think it's confusing because it doesn't show the T type contained in the Result, (i have now seen that you can click on the result and it will show) I will fill a issue instead regarding this
thanks :)

[alexcrichton]

Closing, I think that the naming/convention here is ok, and the real bug was filed under #16096.