Feature: download button for code blocks

[joapuiib]

This PR adds a download button to the code blocks following this syntax:

```lang {data-download="1" title="custom-title.txt"}
Content
```

• Blob downloads data-download="1": Download the code block content. The filename suggested to the browser is resolved in the following order of priority:
  • data-download-filename attribute on the code block
  • title option on the code block
  • Fallback: download.txt

```lang {data-download="https://github.com/user/project/blob/main/project/file.ext"}
Content
```

• URL downloads data-download=url: Create a link button with a download attribute. The filename suggested to the browser is resolved in the following order of priority:
  • data-download-filename attribute on the code block
  • title option on the code block
  • Last path segment of the URL
  • Fallback: download.txt

---

• Download button for code blocks #4

---

Code block buttons now handle translations properly (code.select translation was missing).
English and Catalan translations are updated with this changes.

[joapuiib]

I've set version 10.1.4 version in the docs since I don't think this will merged soon.
Nevertherless, I can change it to any version.