feat: mathematical and chemical content inside code blocks

[deining]

This PR adds the ability to author mathematical formulae inside a math code block:

```math
a^2 + b^2 = c^2
```

renders to:

$$a^2 + b^2 = c^2$$

Now you can also use a chem code block to display a chemical equation:

```chem
\ce{SO4^2- + Ba^2+ -> BaSO4 v}
```

Please have a look at the preview.

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud