Stabilize Wasm target features that are in phase 4 and 5

src/attributes/codegen.md

@@ -273,10 +273,20 @@ attempting to use instructions unsupported by the Wasm engine will fail at load
 time without the risk of being interpreted in a way different from what the
 compiler expected.
 
-Feature     | Description
-------------|-------------------
-`simd128`   | [WebAssembly simd proposal][simd128]
-
+Feature               | Description
+----------------------|-------------------
+`bulk-memory`         | [WebAssembly bulk memory operations proposal][bulk-memory]
+`extended-const`      | [WebAssembly extended const expressions proposal][extended-const]
+`mutable-globals`     | [WebAssembly mutable global proposal][mutable-globals]
+`nontrapping-fptoint` | [WebAssembly non-trapping float-to-int conversion proposal][nontrapping-fptoint]
+`sign-ext`            | [WebAssembly sign extension operators Proposal][sign-ext]
+`simd128`             | [WebAssembly simd proposal][simd128]
+
+[bulk-memory]: https://github.com/WebAssembly/bulk-memory-operations
+[extended-const]: https://github.com/WebAssembly/extended-const
+[mutable-globals]: https://github.com/WebAssembly/mutable-global
+[nontrapping-fptoint]: https://github.com/WebAssembly/nontrapping-float-to-int-conversions
+[sign-ext]: https://github.com/WebAssembly/sign-extension-ops
 [simd128]: https://github.com/webassembly/simd
 
 ### Additional information