[ISSUE][DOCS] Style clean up of AZSL section

[chanmosq]

Describe the issue

This is a follow-up issue to the AZSL documentation PR (https://github.com/o3de/o3de.org/pull/1158). There are some remaining style issues such as:

• Typos
• Code indentation
• Align comments in code where there are many comments, so its cleaner
• Formatting headers

Impacted page(s)

All of the pages in /docs/atom-guide/dev-guide/shaders/azsl/

Expected experience

None.