OpenAPI generation appends `"/openapi.json"` even if the parent path has a forward slash

[jsoverson]

Describe the bug
As the title states. This makes serving the openapi.json from the root (/) problematic because the path matcher won't match ("//openapi.json").

To Reproduce
Run HTTP_PORT=8080 wick run examples/http/rest-router.wick and navigate to "127.0.0.1:8080/openapi-ui"

Expected behavior
The openapi works

Actual behavior
The openapi UI can't find //openapi.json

Environment:

• Build Version: f12a790