feat(file): add support for delimiter args

[M-jerez]

Type of change

✨ New feature (a non-breaking change that adds functionality)

Description

• Limit content from the src file using a delimiter string (must come in pairs) in the src file

<!-- automd:file src="./TEST.md" delimiter="// ##myFunction##"  -->
<!-- /automd -->

• update for delimiter args and also add missing docs for lines args

This is an extension to this PR here #46, we enabling using delimiters strings as src code changes often and lines can also change, over time it can be tedious maintaining lines

Is also relate to this other PR #78 but way more simpler.