docs: updates docs of `findParent` and `find` (#10479) [skip ci]
docs: updates docs of `findParent` and `find` (#10479) [skip ci]

Makes the documentation of `findParent` and `find` consistent and documents their `null` cases.
babel/babel,jridgewell/babel,kaicataldo/babel,babel/babel,kaicataldo/babel,hzoo/babel,babel/babel,hzoo/babel,jridgewell/babel,babel/babel,jridgewell/babel,jridgewell/babel,kaicataldo/babel,hzoo/babel,kaicataldo/babel,hzoo/babel