M8: the shared JBIG2 refusal says no more than it knows

apply works on a copy, so nothing changes when it refuses, but remove_hidden
isn't transactional: a direct caller's document is part changed by then. The
message said nothing was changed for both. The app's callers work on copies.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AmsdeUCdTaD72jkDw2pJKY

crates/redact/src/lib.rs

@@ -76,7 +76,7 @@ pub enum RedactError {
     /// hold, those of marks under the area included, would stay. Counts the images, or 1 for another
     /// reference.
     #[error(
-        "{0} item(s) share JBIG2 symbol data with something being removed and can't be stored without it, so that data, which can show what was removed, would stay in the file; nothing was changed"
+        "{0} item(s) share JBIG2 symbol data with something being removed and can't be stored without it, so that data, which can show what was removed, would stay in the file; this was refused"
     )]
     SharedJbig2Globals(usize),
     #[error(transparent)]