Fix documentation build and broken link

[bouweandela]

Description

The documentation build is broken since #2457 was merged because it included a broken reference. This pull request fixes the reference and also the broken link reported in #2510.

Closes #2510.

Link to documentation: https://esmvaltool--2519.org.readthedocs.build/projects/ESMValCore/en/2519/

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Checklist

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• [x] 🧪 The new functionality is relevant and scientifically sound
• [x] 🛠 This pull request has a descriptive title and labels
• [x] 🧪 and 🛠 Documentation is available
• [x] 🛠 The list of authors is up to date
• [x] 🛠 All checks below this pull request were successful

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[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 94.77%. Comparing base (2247a29) to head (23a9967). Report is 1 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #2519 +/- ## ======================================= Coverage 94.77% 94.77% ======================================= Files 249 249 Lines 14081 14081 ======================================= Hits 13345 13345 Misses 736 736 ```

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