chore: unify include guards to #pragma once

[ahans]

As discussed here.

[no important files changed]

[marcelweikum]

Hey,
I think you forgot to remove the #endif of the "Classes and Headers" topic in the Markdown files below:

concepts/headers/about.md

concepts/headers/introduction.dm

exercises/concept/doctor-data/.docs/introduction.md

Otherwise looks good!

[ahans]

Hey, I think you forgot to remove the #endif of the "Classes and Headers" topic in the Markdown files below:

concepts/headers/about.md

concepts/headers/introduction.dm

exercises/concept/doctor-data/.docs/introduction.md

Otherwise looks good!

Thanks, good catch! Looking at those files again, I realized I actually should not have changed those at all, since they introduce the different ways of using include guards. This also made me look at more md files and I realized there are quite a few more that used a different style of include guards also. I now reverted the changes to those that should include both styles and included changes to the other markdown files.

[marcelweikum]

Looks good to me! 👍

[vaeng]

Hey, I think you forgot to remove the #endif of the "Classes and Headers" topic in the Markdown files below:

concepts/headers/about.md

concepts/headers/introduction.dm

exercises/concept/doctor-data/.docs/introduction.md

Otherwise looks good!

Thanks, good catch! Looking at those files again, I realized I actually should not have changed those at all, since they introduce the different ways of using include guards. This also made me look at more md files and I realized there are quite a few more that used a different style of include guards also. I now reverted the changes to those that should include both styles and included changes to the other markdown files.

Thanks for checking. We need to talk about the different styles in the syllabus, so these should stay.