Fix glossary links for Log and Propagators

[IonDragos2003]

• 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.[^I-know-my-stuff]

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Fixes #6985

Updates glossary link targets:

• Log → links to Logs concept page instead of spec glossary entry
• Propagators → links to language-agnostic Propagators API page instead of Go-specific docs

Additional comments:

Hi team. This is my first PR, and one of my first tries at Open Source contributions. I have used AI in this PR in order to me understand better the requirements and navigate the repo. Based on the comment from the issue itself, seems ultimately quite straightforward.

Happy to answer any questions. Thank you.

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: IonDragos2003 / name: Dragos-georgian Ion (a31bfc8)
• ✅ login: IonDragos2003 / name: Dragos-Georgian Ion (812a499, b92ad56)

[vitorvasc]

Thanks @IonDragos2003 🙌🏼

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