Readme should contain real config.cson examples

### Description

README.md recommends users add the following to config.cson

```cson
"autocomplete-paths":
scopes: [
{ ... },
{ ... },
]
```
But there's no indication what should be put in each scope. Should it be a complete copy of the settings? what is the name of the scope in that case, `scopes`?

One or two real world examples would help a lot

Start with the README.md section containing the autocomplete-paths config.cson snippet and inspect the package's existing configuration expectations. Replace the placeholders with one or two real-world scope examples and clarify what belongs inside each scope. Done means a reader can understand and copy the examples without guessing how scopes are named or structured.

Written by the indexing model from the issue text.