[FEATURE] On line-numbers inside Org Babel Source Blocks.

[divya]

Hello, Org Mode!

I've been using Org Mode for literate programming purposes, and would like to 
have line-numbers within `src` blocks. I am able to export the Org buffer and 
get the line-numbers, but I am unable to do the same with regards to just in 
Org buffers. I am aware of `org-edit-special`, but I would rather appreciate if 
I can just look at a piece of code and know how long it is. I believe a header 
argument can be useful in toggling this.

Since the source blocks can already implement syntax highlighting, font and 
other means of interacting with displaying Babel source blocks, theoretically 
this shouldn't be that difficult to implement? I'd be glad to help implementing 
this feature, if I can be slightly guided on where to refer to look for in the 
codebase.

Regards,

Divya Ranjan