Typescript does not recognize `store: true` on Document Index

[lgtmak]

Typescript DocumentDescriptor type does not recognize a boolean on the store field which makes it hard to use Flexsearch types in code.

flexsearch/index.d.ts

Line 96 in 98c6039

store?: FieldName | FieldName[] | StoreOptions | Array<StoreOptions>;

[ts-thomas]

Update was published, thanks for the report.