Merge #456: Wrap saved story revision counters consistently

Conflict: crates/doc/src/edit.rs: next's thread_frames (append_story); every rev += 1 is rev.wrapping_add(1)
Conflict: crates/engine/src/cmd/fonts.rs: next's replace (the local-formatting pass moved out of this hunk)
Conflict: crates/engine/src/cmd/text.rs: next's format_chars (apply_char_attrs, typing format); rev += 1 is rev.wrapping_add(1)

crates/engine/src/cmd/style.rs

@@ -623,7 +623,7 @@ fn rename_style(d: &mut designcraft_doc::Document, para: bool, from: &str, to: &
                     rename_char_refs(&mut f.para, from, to);
                 }
             }
-            st.rev += 1;
+            st.rev = st.rev.wrapping_add(1);
         });
     }
 }