synopsis: `Capture` can be `Lenient`
issues: #1155
prs: #1156
significance: significant
description: {

You can specify a lenient capture as

```haskell
:<|> "capture-lenient"  :> Capture' '[Lenient] "foo" Int :> GET
```

which will make the capture always succeed. Handlers will be of the
type `Either String CapturedType`, where `Left err` represents
the possible parse failure.

}