[en] fix typo in content/en/docs/getting-started/reference-applicatio…

[jmsundar]

…n-specification.md

• I have read and followed the Contributing docs, especially the "First-time contributing?" section.
• This PR has content that I did not fully write myself.
  • I used AI and I have read and followed the Generative AI Contribution Policy.
• I have the experience and knowledge necessary to understand, review, and validate all content in this PR.¹

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This PR fixes a single typo, and gives me the ability to sign the Corporate CLA, as directed by EasyCLA support.

Footnotes

1. Yes, I can answer maintainer questions about the content of this PR, without using AI. ↩