Rollup merge of #90704 - ijackson:exitstatus-comments, r=joshtriplett

Unix ExitStatus comments and a tiny docs fix

Some nits left over from #88300

library/std/src/sys/unix/process/process_unix.rs

@@ -617,6 +617,9 @@ impl Process {
 }
 
 /// Unix exit statuses
+//
+// This is not actually an "exit status" in Unix terminology.  Rather, it is a "wait status".
+// See the discussion in comments and doc comments for `std::process::ExitStatus`.
 #[derive(PartialEq, Eq, Clone, Copy)]
 pub struct ExitStatus(c_int);