`nim doc --project` is misused
`nim doc --project` is supposed to be for several modules at once (and generates a single theindex.html) so i dont' understand this:
```
  execCmd "nim doc --project --index:on nimterop/cimport"
  execCmd "nim doc --project --index:on nimterop/git"
  execCmd "nim doc --project --index:on nimterop/plugin"
```

instead shd probably be:
```
execCmd "nim doc --project --index:on nimterop/all" #which imports all  (in case there's not already such module importing `all`)
```
