fix: verify suffix range ends at file boundary in matches_requested_range

The suffix match only checked that the range length equaled the
requested suffix, but did not verify the range ends at the file
boundary. When size is known, also check `range.end() + 1 == size`.

Author: paolobarbolini

src/headers/content_range.rs

@@ -31,8 +31,10 @@ impl HttpContentRange {
                 HttpRange::Range(OrderedRange { start, end }),
                 HttpContentRange::Bound(Bound { range, .. }),
             ) => start == range.start() && end == range.end(),
-            (HttpRange::Suffix(suffix), HttpContentRange::Bound(Bound { range, .. })) => {
-                (range.end() - range.start()).checked_add(1) == Some(suffix)
+            (HttpRange::Suffix(suffix), HttpContentRange::Bound(Bound { range, size })) => {
+                let length_matches = (range.end() - range.start()).checked_add(1) == Some(suffix);
+                let ends_at_boundary = size.is_none_or(|size| range.end() + 1 == size);
+                length_matches && ends_at_boundary
             }
             (
                 HttpRange::StartingPoint(n),