Adds CancellableResultTask functions

[TheAngryByrd]

Proposed Changes

• Adds CancellableResultTask functions
• Updates IcedTasks 0.5.1

Types of changes

What types of changes does your code introduce to FsToolkit.ErrorHandling?
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• New feature (non-breaking change which adds functionality)

Checklist

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• Build and tests pass locally
• I have added tests that prove my fix is effective or that my feature works (if appropriate)
• I have added necessary documentation (if appropriate)

Further comments

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