message: doc(example): example of 404 handler
diff: -import { Effect, combineRoutes, matchPath, matchType } from '@marblejs/core';
  -import { map } from 'rxjs/operators';
  +import { Effect, HttpError, HttpStatus, combineRoutes, matchPath, matchType } from '@marblejs/core';
  +import { throwError } from 'rxjs';
  +import { map, switchMap } from 'rxjs/operators';
  import { user$ } from './user.controller';
  const root$: Effect = request$ => request$
  @@ -11,7 +12,16 @@ const root$: Effect = request$ => request$
  })),
  );
  +const notFound$: Effect = request$ => request$
  + .pipe(
  + matchPath('*'),
  + matchType('*'),
  + switchMap(() =>
  + throwError(new HttpError('Route not found', HttpStatus.NOT_FOUND))
  + )
  + );
  +
  export const api$ = combineRoutes(
  '/api/v1',
  - [ root$, user$ ],
  + [ root$, user$, notFound$ ],
  );
  