docs: fix a typo in modal-ref.ts (#3859)
docs: fix a typo in modal-ref.ts (#3859)

Typo: Mobal -> Modal
fbasso/ng-bootstrap,maxokorokov/core,ng-bootstrap/ng-bootstrap,ng-bootstrap/ng-bootstrap,maxokorokov/core,maxokorokov/core,jnizet/ng-bootstrap,maxokorokov/core,fbasso/ng-bootstrap,jnizet/ng-bootstrap,ng-bootstrap/ng-bootstrap,jnizet/ng-bootstrap,jnizet/ng-bootstrap,fbasso/ng-bootstrap,fbasso/ng-bootstrap,ng-bootstrap/ng-bootstrap