choosenim installs Nim/config/nim.cfg  but not Nim/config/config.nims
choosenim installs Nim/config/nim.cfg  but not Nim/config/config.nims

Nim/config/config.nims currently only contains this
```nim
when defined(nimHasCppDefine):
  cppDefine "errno"
  cppDefine "unix"
```
but might contain more in the future. In any case, this is a bug

```
\ls /Users/timothee/.choosenim/toolchains//nim-1.2.0/config
nim.cfg         nimdoc.cfg      nimdoc.tex.cfg
```