More distinguishable org-block

[laooree]

Hello everyone!

I use quite a lot org-mode for literate programming, and I think it would be useful to better highlight org-block with respect to literate text.

Ideally, a darker background for org-block would be the best, but the darkest color is already used as normal background. Thus, I thought about setting a lighter the background for the faces org-block-begin-line and org-block-end-line, using a color such as nord1.

The following picture shows what I mean:

What is in picture is achieved with the following face settings in the theme code:

`(org-block-begin-line ((,class (:foreground ,nord7 :background ,nord1 :extend t))))
`(org-block-end-line ((,class (:foreground ,nord7 :background ,nord1 :extend t))))

What do you think about it? Are there other enhancements possible to achieve the aforementioned goal?