Notify to Disable old standalone extensions

There is a number of extensions that people have installed that will interfere with Modern Fortran.
A warning should display about disabling them, e.g. something like 

>The following extension ${ext} is no longer needed with Modern Fortran and can cause Modern Fortran to stop working, please Disable it.

- `hansec.fortran-ls`
- `ekibun.fortranbreaker`

