message: serlo-injection: simplify createURL
diff: @@ -13,14 +13,9 @@ import { useSerloInjectionConfig } from './config'
  import { SerloInjectionRenderer } from './renderer'
  const createURL = (id: string) => {
  - if (id.startsWith('/') || id.startsWith('\\')) {
  - return (
  - 'https://de.serlo.org/' +
  - id.substring(1, id.length) +
  - '?contentOnly&hideBreadcrumbs'
  - )
  - }
  - return 'https://de.serlo.org/' + id + '?contentOnly&hideBreadcrumbs'
  + const pureId =
  + id.startsWith('/') || id.startsWith('\\') ? id.substring(1) : id
  + return `https://de.serlo.org/${pureId}?contentOnly`
  }
  const PlaceholderWrapper = styled.div({
  