INTRASITE_LINK_REGEX is parsed in Markdown headers

[aguadopd]

• I have read the Filing Issues and subsequent “How to Get Help” sections of the documentation.
• I have searched the issues (including closed ones) and believe that this is not a duplicate.

• OS version and name: openSUSE Tumbleweed 20240412
• Python version: 3.11.8
• Pelican version: 4.9.1
• Link to theme: using included "Simple", but not relevant.
• Links to plugins: None
• Link to a Gist with the contents of your settings file: Fresh installation. Added STATIC_PATHS = ["."] for {static} example.

Issue

Scenario

cat content/post3.md:

Title: Post3
Date: 2010-12-03 10:20
Modified: 2010-12-05 19:30
Category: Python
Tags: pelican, publishing
Slug: post3
Authors: Alexis Metaireau, Conan Doyle
Summary: Short version for index and feeds
-----

# **SHOULD WORK**: The following words are between curly braces: {this is between curly braces}

## **SHOULD WORK**: The following words are between curly braces: {this is between curly braces}

### **SHOULD WORK**: The following words are between curly braces: {this is between curly braces}


- The following words are between curly braces: {this is between curly braces}

# **WORKS AS EXPECTED**: The following words are between curly braces: `{this is between curly braces}`

- The following words are between curly braces: {this is between curly braces}

Expected behavior:

Content in curly braces (actually, matching INTRASITE_LINK_REGEX) in titles is not treated as something special.

Current behavior:

It's parsed as INTRASITE_LINK_REGEX, and then not shown. HTML generated for the previous example:

  <h1 between braces curly is this><strong>SHOULD WORK</strong>: The following words are between curly braces:</h1>
<h2 between braces curly is this><strong>SHOULD WORK</strong>: The following words are between curly braces:</h2>
<h3 between braces curly is this><strong>SHOULD WORK</strong>: The following words are between curly braces:</h3>
<ul>
<li>The following words are between curly braces: {this is between curly braces}</li>
</ul>
<h1><strong>WORKS AS EXPECTED</strong>: The following words are between curly braces: <code>{this is between curly braces}</code></h1>
<ul>
<li>The following words are between curly braces: {this is between curly braces}</li>
</ul>

<h1 between braces curly is this> suggests an ordered list or set built with the parsed words.