[feature request] More direct source line mapping

Since the compiler can already append a comment to each Lua line saying what Yuescript line it came from, it would be nice if there were an option to instead just put all Lua code on the same line as the Yuescript code that produced it, as well as preserving empty lines.

For example, the code:

1| x = if this
2|     foo()
3| 
4| else
5|     bar()

would be compiled like this:

1| local x
2| if this then
3|     x = foo()
4| else
5|     x = bar()
6| end

My suggestion would be to allow for it to be compiled to something more like this:

1| local x; if this then
2|     x = foo()
3| 
4| else
5|     x = bar(); end

The goal is to make line numbers in tracebacks and debugging info map directly to their according Yuescript line, meaning that it would no longer be necessary to first look which Lua line the error occurred on and then go to the Yuescript line that produced it. Instead, we could simply go to the error line directly in the Yuescript file.

The issue names no source file, test, or entry point. Start by tracing the compiler's existing per-line Lua comments and line-preservation behavior; done means an option produces Lua line mappings that directly match Yuescript lines, including empty lines.