feat(exception): expose description as a property in HttpException

[itizarsa]

Description

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Issue Ticket Number

Fixes #107

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Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to
  not work as expected)
• This change requires a documentation update

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Checklist:

• I have run deno lint AND deno fmt AND deno task test and got no
  errors.
• I have followed the contributing guidelines of this project as mentioned
  in CONTRIBUTING.md
• I have checked to ensure there aren't other open
  Pull Requests for the same
  update/change?
• I have performed a self-review of my own code
• I have made corresponding changes needed to the documentation

[itizarsa]

@Sorikairox One potential problem is that the description will be added to the response if the users don't have custom exception filters.

[Sorikairox]

@itizarsa I think it's ok, adding attributes shouldn't break existing integrations