Code block tweaks

currently when i paste a big chunk of code in code block, it makes high block of code with horizontal scrollbar because of couple of long lines 🤔

it would be better to:

1) make it collapsed by default with overflow-y: auto with possibility to expand it to full height by some button in sticky header or footer

2) wrap long lines of code by adding white-space: pre-wrap;

which will change its look from this 🤐

to this 😎