Support for Code Block Line Highlighting in YFM

[martyanovandrey]

It would be beneficial if YFM supported line highlighting within code blocks. This feature is frequently used in documentation to draw attention to critical lines of code, demonstrate changes, or emphasize specific parts of the code.

Proposed Solution

Introduce a new prop, {1,3-5}, within the language meta string of code blocks.

Syntax Example

```javascript {1}
const example = "This is a code block.";
console.log(examples);

Reference: https://docusaurus.io/docs/markdown-features/code-blocks#line-numbering