fix typo

[khadkarajesh]

Proposed Changes

Fixed typo in documentation

Types of Changes

What types of changes does your code introduce to this project?
Put an x in the boxes that apply

• Bugfix (non-breaking change which fixes issue #NNNN)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation (correction or otherwise)
• Cosmetics (whitespace, appearance)

Checklist

Put an x in the boxes that apply. You can also fill these out after
creating the PR. If you're unsure about any of them, don't hesitate to
ask on the
pika-python
mailing list. We're here to help! This is simply a reminder of what we
are going to look for before merging your code.

• I have read the CONTRIBUTING.md document
• All tests pass locally with my changes
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)

[lukebakken]

Thank you!