Conform function headers to coding guidelines

[Phyma]

When merged this pull request will:

• Fix every header on all files that i have on my fork
• Tested with Silentspikes python script Add public function documentation script #5253
• Even if the other thing is not accepted this is still good
• Alot of things that i have done is switch to current header, add example, add public and fixed "ReturnValue" to "Return Value"

I believe this is a label "impact/trivial" because it's only headers

[jonpas]

This should be None, I noticed it was wrong in some other files before as well.

[kymckay]

The script will now complain about this too after latest commit 😄

[Phyma]

Yeay. Well we can put this as WIP so I can fix this in the same tempo that silentspike updates the script and we just do both at the same time :)

I was just bored and didnt feel like scripting so did this.

[Phyma]

Done! No more errors! Plus new version of the software only public functions

[jonpas]

I say merge this ASAP to prevent merge conflicts. If there are other things to fix in headers, they can be done separately from this.

[bux]

DO IT NAOW!