feat: Add Require and Check helper methods

[PI-Gorbo]

Context

Starting from this Task #281, I have implemented two new methods for Result, TaskResult and AsyncResult.

Method 1 - Require

In the Issue i called it ensure, because that is what the C#FunctionalExtensions however I decided to name it require to be more in line with the other requireX functions.

Require applies a predicate to the Ok value of a Result. If the predicate is false, then a new Error Result is returned with a user provided error.

Method 2 - Check

Same as described in the github task, check applies a more general function of the from 'ok -> Result<unit, 'error> to the Ok value of a Result. It returns the original Ok value is the function returns Ok (), otherwise it returns the new error returned by the applied function.

I have added docs.

I am super open to feedback and changes! Please fire away

[TheAngryByrd]

Thanks for this! Sorry holidays have made reviewing hectic.

Ran the CI and got:

[Expecto 00:00:18.7573892] FsToolkit.ErrorHandling.Tests: Found duplicated test names, these names are: [["All Tests.Result Tests.check tests.Using the result value in the predicate"]]

You'll have to disambiguate one of the tests.

[PI-Gorbo]

Happy new year! Same with the holidays getting in my way.
I've sent a fix - I had a duplicated test. Sorry about that 🤦