Add basic docs for timer and semaphore syscalls

[nathanwhyte]

Helping with issue #353

Added (very) basic documentation to syscalls in timer.rs and semaphore.rs

I used Linux man pages as a reference when writing these.

[mkroening]

Thanks for working on this. :)

Generally, this looks good. I would like these docs to be a bit more rusty, though. Specifically, an items documentation should start with a short sentence, then have an empty line, and then go into details. The details should also be relevant for API usage and not be implementation details. Comments about implementation details are welcome as well, but should be marked as documentation. Implementation details often fit better inside the function to where stuff happens, but might also be fit for placement outside the function.

Made-up example:

/// Yields to the executor.
///
/// This function can be used for ...
// We save the task handle in ... and reschedule.
extern "C" fn sys_yield () {

For more information see:

• https://doc.rust-lang.org/rustdoc/how-to-write-documentation.html
• https://rust-lang.github.io/api-guidelines/documentation.html
• The standard library documentation as example.

PS: Remember punctuation at the end of sentences in the doc comments.

[stlankes]

bors r+

[stlankes]

@nathanwhyte Thanks for the support!

[bors]

Build succeeded:

• Build
• Check
• Check docs
• ci/gitlab/git.rwth-aachen.de
• Clippy
• Format
• Run RustyHermit (aarch64)
• Run RustyHermit (x86_64)
• Test

[nathanwhyte]

Thank you to everyone for being accommodating while I was working on these issues. Y'all saved me from a bad project grade by helping me solve them! 😆