#13402 3e7b498 Thanks @ematipico! - Adds a new experimental flag called experimental.preserveScriptOrder that renders <script> and <style> tags in the same order as they are defined.

When rendering multiple <style> and <script> tags on the same page, Astro currently reverses their order in your generated HTML output. This can give unexpected results, for example CSS styles being overridden by earlier defined style tags when your site is built.

With the new preserveScriptOrder flag enabled, Astro will generate the styles in the order they are defined:

```js title="astro.config.mjs" import { defineConfig } from 'astro/config';

export default defineConfig({ experimental: { preserveScriptOrder: true, }, }); ```

For example, the following component has two <style> tags, and both define the same style for the body tag:
```
<p>I am a component</p>
<style>
  body {
    background: red;
  }
</style>
<style>
  body {
    background: yellow;
  }
</style>
```
Once the project is compiled, Astro will create an inline style where yellow appears first, and then red. Ultimately, the red background is applied:
```
body {
  background: #ff0;
}
body {
  background: red;
}
```
When experimental.preserveScriptOrder is set to true, the order of the two styles is kept as it is, and in the style generated red appears first, and then yellow:
```
body {
  background: red;
}
body {
  background: #ff0;
}
```
This is a breaking change to how Astro renders project code that contains multiple <style> and <script> tags in the same component. If you were previously compensating for Astro's behavior by writing these out of order, you will need to update your code.

This will eventually become the new default Astro behavior, so we encourage you to add this experimental style and script ordering as soon as you are able! This will help us test the new behavior and ensure your code is ready when this becomes the new normal.

For more information as this feature develops, please see the experimental script order docs.

#13352 cb886dc Thanks @delucis! - Adds support for a new experimental.headingIdCompat flag

By default, Astro removes a trailing - from the end of IDs it generates for headings ending with special characters. This differs from the behavior of common Markdown processors.

You can now disable this behavior with a new configuration flag:
```
// astro.config.mjs
import { defineConfig } from 'astro/config';

export default defineConfig({
  experimental: {
    headingIdCompat: true,
  },
});
```
This can be useful when heading IDs and anchor links need to behave consistently across your site and other platforms such as GitHub and npm.

If you are using the rehypeHeadingIds plugin directly, you can also pass this new option:
```
// astro.config.mjs
import { defineConfig } from 'astro/config';
import { rehypeHeadingIds } from '@astrojs/markdown-remark';
import { otherPluginThatReliesOnHeadingIDs } from 'some/plugin/source';

export default defineConfig({
  markdown: {
    rehypePlugins: [
      [rehypeHeadingIds, { experimentalHeadingIdCompat: true }],
      otherPluginThatReliesOnHeadingIDs,
    ],
  },
});
```
#13311 a3327ff Thanks @chrisirhc! - Adds a new configuration option for Markdown syntax highlighting excludeLangs

This option provides better support for diagramming tools that rely on Markdown code blocks, such as Mermaid.js and D2 by allowing you to exclude specific languages from Astro's default syntax highlighting.

This option allows you to avoid rendering conflicts with tools that depend on the code not being highlighted without forcing you to disable syntax highlighting for other code blocks.

The following example configuration will exclude highlighting for mermaid and math code blocks:
```
import { defineConfig } from 'astro/config';

export default defineConfig({
  markdown: {
    syntaxHighlight: {
      type: 'shiki',
      excludeLangs: ['mermaid', 'math'],
    },
  },
});
```
Read more about this new option in the Markdown syntax highlighting configuration docs.

Patch Changes

#13404 4e78b4d Thanks @ascorbic! - Fixes a bug in error handling that saving a content file with a schema error would display an "unhandled rejection" error instead of the correct schema error
#13379 d59eb22 Thanks @martrapp! - Fixes an edge case where the client router executed scripts twice when used with a custom swap function that only swaps parts of the DOM.
#13393 6b8fdb8 Thanks @renovate! - Updates primsjs to version 1.30.0, which adds support for more languages and fixes a security advisory which does not affect Astro.
#13374 7b75bc5 Thanks @ArmandPhilippot! - Fixes the documentation of the i18n configuration where manual was presented as a key of routing instead of an available value.
#13380 9bfa6e6 Thanks @martrapp! - Fixes an issue where astro:page-load fires before all scripts are executed
#13407 0efdc22 Thanks @ascorbic! - Displays correct error message when sharp isn't installed
Updated dependencies [cb886dc, a3327ff]:
- @astrojs/markdown-remark@6.3.0