never advance seek position in `std.Io.Reader.peekDelimiterExclusive` (#24899)
* extend std.Io.Reader.peekDelimiterExclusive test to repeat successful end-of-stream path (fails)
* fix std.Io.Reader.peekDelimiterExclusive to not advance seek position in successful end-of-stream path
6cdbf4223cRohlem committed on 8/19/2025, 11:01:40 PM· committed by Andrew Kelleyparentf54f061