Feature Request: Comment range

Currently the code injection allows you to specify lines of code from a file:

 <!-- AUTO-GENERATED-CONTENT:START (CODE:src=./relative/path/to/code.js&lines=22-44) -->
 This content will be dynamically replaced with code from the file lines 22 through 44
 <!-- AUTO-GENERATED-CONTENT:END -->

This can be dificult to maintain as line numbers are subject to change with API changes. An easier way to do this would be to select between specified comment blocks. Here's a simple example:

 <!-- AUTO-GENERATED-CONTENT:START (CODE:src=./relative/path/to/code.js&block=BLOCK1) -->
 This content will be dynamically replaced with code (from the file) found between comments containing "BLOCK1".
 <!-- AUTO-GENERATED-CONTENT:END -->

code.js :

// ...

// <BLOCK1>
console.log("This will get selected");
// </BLOCK1>

Happy to help out with a PR.

Start by locating the code-injection handling that currently supports the lines option, then inspect how source ranges are parsed and extracted. Use the example code.js block markers as the expected input; done means a block selector can replace the line-range selector and extracts the content between matching markers.