Add documentation for `MemorySize`

[funnyboy-roks]

Add documentation to the methods generated for the MemorySize methods generated here:

leucite/src/prlimit.rs

Lines 9 to 33 in 72e36c4

	macro_rules! impl_memsz {
	($from_fn: ident => $param: ident * $expr: expr) => {
	#[inline]
	pub fn $from_fn($param: u64) -> Self {
	Self($param * $expr)
	}
	#[inline]
	pub fn $param(self) -> u64 {
	self.0 / $expr
	}
	};
	}
	impl MemorySize {
	impl_memsz!(from_bytes => bytes * 1);
	impl_memsz!(from_kb => kilobytes * 1000);
	impl_memsz!(from_mb => megabytes * 1000 * 1000);
	impl_memsz!(from_gb => gigabytes * 1000 * 1000 * 1000);
	impl_memsz!(from_kib => kibibytes * 1024);
	impl_memsz!(from_mib => mebibytes * 1024 * 1024);
	impl_memsz!(from_gib => gibibytes * 1024 * 1024 * 1024);
	}

The documentation should specifically cover the math used (1024 vs 1000)