Fix typos in = combining_requests.mdx

[mohn93]

Related Issues

fixes #your-issue-number

Checklist

Before you create this PR confirm that it meets all requirements listed below by checking the relevant checkboxes ([x]).

• I have updated the CHANGELOG.md of the relevant packages.
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  ## Unreleased fix/major/minor
  
  - Description of your change. (thanks to @yourGithubId)

• If this contains new features or behavior changes,
  I have updated the documentation to match those changes.

[rrousselGit]

Thanks!