Sphinx content post-processing with JavaScript

layout.html

<!--
Javascript to render AIRFLOW-XXX and PR references in text
as HTML links.

Overrides extrahead block from sphinx_rtd_theme
https://www.sphinx-doc.org/en/master/templating.html
-->

{% extends "!layout.html" %}

{% block extrahead %}
  {{ super() }}
  <script>
    document.addEventListener('DOMContentLoaded', function() {
      var el = document.getElementById('changelog');
      if (el !== null ) {
        // [AIRFLOW-...]
        el.innerHTML = el.innerHTML.replace(
            /\[(AIRFLOW-[\d]+)\]/g,
            `<a href="https://issues.apache.org/jira/browse/$1">[$1]</a>`
        );
        // (#...)
        el.innerHTML = el.innerHTML.replace(
            /\(#([\d]+)\)/g,
            `<a href="https://github.com/apache/airflow/pull/$1">(#$1)</a>`
        );
      };
    })
  </script>
{% endblock %}