Add documentation/comments to infinite loops

[amab8901]

After #806 has been merged, go through every empty loop (marked by #[allow(clippy::empty_loop)]) and add explanation for why the empty loop is necessary and criteria for replacing it with something else.

Each empty loop should have its own independent explanation case-by-case (rather than having a single explanation that covers multiple empty loops, or copy+pasting boilerplate). Because that extra scrutiny might reveal an (otherwise hard to spot) opportunity for improvement to future system developers.

@kevinaboos

[kevinaboos]

Thanks for filing this!