Update floating-point-support.md

[EddieBreeveld]

Explain what "ulp" stands for

[prmerger-automator]

@EddieBreeveld : Thanks for your contribution! The author(s) have been notified to review your proposed change.

[opbld31]

Docs Build status updates of commit 4549fa0:

✅ Validation status: passed

File	Status	Preview URL	Details
docs/c-runtime-library/floating-point-support.md	✅Succeeded

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[Court72]

@TylerMSFT

Can you review the proposed changes? IMPORTANT: When the changes are ready for publication, add a #sign-off comment to signal that the PR is ready for the review team to merge.

#label:"aq-pr-triaged"
@MicrosoftDocs/public-repo-pr-review-team

[TylerMSFT]

Thank you, @EddieBreeveld , for adding this clarifying parenthetical.

[TylerMSFT]

#sign-off