Assembly format fixup

See merge request os/gi4_uebung08!6

Use consistent indentation

See merge request os/gi4_uebung08!5

Fix typo in task 2

See merge request os/gi4_uebung08!4

Reformat tables

See merge request os/gi4_uebung08!3

Correctly declare markdown assembly code block as 'nasm'

See merge request os/gi4_uebung08!1

The table will be smaller, but programmers will be less confused.

All C streams are flushed when returning from main.

We are linking against a C library anyways.

See: https://www.nasm.us/xdoc/2.14.02/html/nasmdoc3.html#section-3.9

See: https://www.nasm.us/xdoc/2.14.02/html/nasmdoc3.html#section-3.4.2

See: https://github.com/rouge-ruby/rouge/pull/457/