Rollup merge of #69584 - zantysor:fix-saturating-duration-since-comment, r=varkor
Rollup merge of #69584 - zantysor:fix-saturating-duration-since-comment, r=varkor

Correct comment to match behavior

Corrects the header comment on `saturating_duration_since` to match the behavior of returning 0 if the other timestamp is _later_ than the invocant, not earlier,

This is purely a documentation change, so hopefully it doesn't require an issue; if it does, I'll open one and resubmit.

graydon/rust,graydon/rust,aidancully/rust,aidancully/rust,graydon/rust,aidancully/rust,aidancully/rust,graydon/rust,aidancully/rust,aidancully/rust,graydon/rust,graydon/rust