add note about unsupported-platforms to README.md

existing Windows (.NET) template is kept in `unsupported-platforms`
for now (at least)

Author: Christopher J. Brody

README.md

@@ -36,7 +36,7 @@ This tool based on [`react-native-create-library`](https://www.npmjs.com/package
     - requires the [`react-native-tvos`](https://www.npmjs.com/package/react-native-tvos) fork, with minimum version of 0.60 ref:  [react-native-community/react-native-tvos#11](https://github.com/react-native-community/react-native-tvos/issues/11)), [issue #95](https://github.com/brodybits/create-react-native-module/issues/95)
     - unstable with very limited testing, with limited if any active support from the primary maintainer [@brodybits](https://github.com/brodybits) (see [issue #127](https://github.com/brodybits/create-react-native-module/issues/127))
 - Out-of-tree platforms
-  - Windows - no longer supported for reasons discussed in [issue #23](https://github.com/brodybits/create-react-native-module/issues/23) and [issue #43](https://github.com/brodybits/create-react-native-module/issues/43)
+  - Windows - no longer supported for reasons discussed in [issue #23](https://github.com/brodybits/create-react-native-module/issues/23) and [issue #43](https://github.com/brodybits/create-react-native-module/issues/43) (existing Windows (.NET) template is kept in `unsupported-platforms` for now, at least)
   - for future consideration: macOS (see [issue #94](https://github.com/brodybits/create-react-native-module/issues/94))
 - Node.js pre-10 support is deprecated and will be removed in the near future (see [issue #38](https://github.com/brodybits/create-react-native-module/issues/38))