fix typo

[WeihanLi]

Proposed Changes

Add a space to fix a typo

Types of Changes

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

• [ ] Bug fix (non-breaking change which fixes issue #NNNN)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause an observable behavior change in existing systems)
• [x] Documentation improvements (corrections, new content, etc)
• [ ] Cosmetic change (whitespace, formatting, etc)

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 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
• [ ] I have signed the CA (see https://cla.pivotal.io/sign/rabbitmq)
• [ ] 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)
• [ ] Any dependent changes have been merged and published in related repositories

Further Comments

If this is a relatively large or complex change, kick off the discussion by explaining why you chose the solution you did and what alternatives you considered, etc.

[pivotal-cla]

@WeihanLi Please sign the Contributor License Agreement!

Click here to manually synchronize the status of this Pull Request.

See the FAQ for frequently asked questions.

[pivotal-cla]

@WeihanLi Thank you for signing the Contributor License Agreement!

[michaelklishin]

Thank you.