Update the documentation of -C force-unwind-tables

Author: hyd-dev

src/doc/rustc/src/codegen-options/index.md

@@ -149,8 +149,7 @@ values:
 
 * `y`, `yes`, `on`, or no value: Unwind tables are forced to be generated.
 * `n`, `no`, or `off`: Unwind tables are not forced to be generated. If unwind
-  tables are required by the target or `-C panic=unwind`, an error will be
-  emitted.
+  tables are required by the target an error will be emitted.
 
 The default if not specified depends on the target.