Extend the `XMonad.Hooks.ManageHelpers` EDSL

[slotThe]

Feature Description

There have been more and more people on IRC wanting something like (=?), but for isPrefixOf, isInfixOf, or another function. I think some of these would make a great addition to the EDSL that's defined by X.ManageHook and extended by X.H.ManageHelpers.

Suggestions:

• (^?) as a lifted version of isPrefixOf,
• (~?) as a lifted version of isInfixOf,
• ($?) as a lifted version of isSuffixOf.

Further, it sounds like a good idea to tell users in the docs of either X.H.ManageHelpers, or X.ManageHook how to define these small functions; since it's mostly just one call to fmap + the function, this is probably less intimidating than it would initially seem.

If you want to start contributing to xmonad, this is an ideal issue! Feel free to ask for help in this issue, on IRC, Matrix, or via another channel of your choosing :tada:

[astynax]

I would like to try!

[slotThe]

@astynax Awesome! I've assigned the issue to you