[8.10] [DOCS] Make landing page links relative (#166314) (#166333)

# Backport

This will backport the following commits from `main` to `8.10`:
- [[DOCS] Make landing page links relative
(#166314)](#166314)

<!--- Backport version: 8.9.7 -->

### Questions ?
Please refer to the [Backport tool
documentation](https://github.com/sqren/backport)

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Make landing page links relative (#166314)\n\n**Problem:**\r\nThe links
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Make landing page links relative (#166314)\n\n**Problem:**\r\nThe links
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Make landing page links relative (#166314)\n\n**Problem:**\r\nThe links
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Co-authored-by: James Rodewig <[email protected]>

docs/landing-page.asciidoc

@@ -71,8 +71,8 @@
       </a>
     </p>
     <p>
-      <a class="inline-block mr-3" href="https://www.elastic.co/guide/en/kibana/8.10/whats-new.html">What's new</a>
-      <a class="inline-block mr-3" href="https://www.elastic.co/guide/en/kibana/8.10/release-notes.html">Release notes</a>
+      <a class="inline-block mr-3" href="whats-new.html">What's new</a>
+      <a class="inline-block mr-3" href="release-notes.html">Release notes</a>
       <a class="inline-block mr-3" href="install.html">Install</a>
     </p>
   </div>