Header text is truncated sometimes - Proposed fix

[yccheok]

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Describe the bug
Header text is truncated sometimes, randomly

Checklist

• I can reproduce this issue with a vanilla SwiftUI project.
• I can reproduce this issue using the main branch of this package.
• This bug hasn't been addressed in an existing GitHub issue.

Steps to reproduce
It happens randomly. This is the markdown text I am using

# Exploring the Fragility of Life in an Infinite Universe

## The Central Question of Existence
- The primary philosophical inquiry is: **What does it mean to live a finite, fragile life in an infinite, eternal universe?**
- The universe contains approximately **2 trillion galaxies**, with the Milky Way housing around **400 billion stars**.
- Despite the vastness, Earth is the only known place where life and meaning exist.

## The Scale of the Universe
- Light takes over **100,000 years** to traverse a galaxy, emphasizing the immense scale of the universe.
- The visible universe is likely just a small portion of a potentially infinite cosmos.
- The challenge of visualizing this scale is acknowledged; it is beyond human comprehension.

## Human Significance in the Universe
- Although humans are physically insignificant in the grand scheme, we are unique as **collections of atoms** that can think and create.
- The idea that the universe understands itself through human consciousness is highlighted, referencing **Carl Sagan**.
- The rarity of intelligent life is suggested, as there is no evidence of other civilizations in our galaxy despite extensive searches.

## The Development of Life on Earth
- Life on Earth began around **3.8 billion years ago**, with complex life taking over **3 billion years** to evolve from single-celled organisms.
- The timeline from simple to complex life is significant, indicating the precarious nature of life's evolution.
- The extinction of dinosaurs **65 million years ago** allowed mammals to thrive, leading to the emergence of human civilization.

## Conclusion: The Precarious Nature of Civilization
- The absence of evidence for other civilizations suggests that Earth may be the **only place** where intelligent life has developed.
- The survival and evolution of life are portrayed as fragile and dependent on a series of fortunate events in a violent universe.

Expected behavior
Header text without truncation

Screenshots
I avoid this is to use the following

// https://stackoverflow.com/a/56558187/72437
.fixedSize(horizontal: false, vertical: true)

For instance,

.heading1 { configuration in
  VStack(alignment: .leading, spacing: 0) {
    configuration.label
      // https://stackoverflow.com/a/56558187/72437
      .fixedSize(horizontal: false, vertical: true)
      .relativePadding(.bottom, length: .em(0.3))
      .relativeLineSpacing(.em(0.125))
      .markdownMargin(top: 24, bottom: 16)
      .markdownTextStyle {
        FontWeight(.semibold)
          FontSize(.em(1.45))
        ForegroundColor(Color(UIColor.tintColor))
      }
    Divider().overlay(Color.divider)
  }
}

It looks like

Version information

• MarkdownUI: 2.4.1
• OS: iOS 16
• Xcode: 16.0

Additional context
Can I propose such a fix to?

https://github.com/gonzalezreal/swift-markdown-ui/blob/a9c7615fb50323069c2979c69263973aa1b24a8f/Sources/MarkdownUI/Theme/Theme%2BGitHub.swift