doc: update decorator documentation to reflect actual policy

- Remove misleading 'will soon be supported' language
- Remove 'temporary limitation' claim
- Clarify that Node.js does not provide polyfills
- State that decorators will be supported when implemented natively
- Apply team member feedback for better clarity

Refs: #60282

doc/api/typescript.md

@@ -160,7 +160,7 @@ namespace A {
 
 Since Decorators are currently a [TC39 Stage 3 proposal](https://github.com/tc39/proposal-decorators),
 they are not transformed and will result in a parser error.
-Node.js does not provide polyfills for decorators and will not support them until
+Node.js does not provide polyfills and thus will not support decorators until
 they are supported natively in JavaScript.
 
 In addition, Node.js does not read `tsconfig.json` files and does not support