Improve type support for ts #645

[Freymaurer]

Closes #645

Transpiling Feliz ReactComponent to typescript:

    [<ReactComponent(true)>]
    static member TermSearch(
        onTermSelect: Term option -> unit,
        term: Term option,
        ?parentId: string,
        ?termSearchQueries: ResizeArray<string * SearchCall>,
        ?parentSearchQueries: ResizeArray<string * ParentSearchCall>,
        ?allChildrenSearchQueries: ResizeArray<string * AllChildrenSearchCall>,
        ?advancedSearch: U2<AdvancedSearch, bool>,
        ?onFocus: unit -> Fable.Core.JS.Promise<unit>,
        ?onBlur: unit -> Fable.Core.JS.Promise<unit>,
        ?onKeyDown: Browser.Types.KeyboardEvent -> Fable.Core.JS.Promise<unit>,
        ?showDetails: bool,
        ?debug: bool,
        ?disableDefaultSearch: bool,
        ?disableDefaultParentSearch: bool,
        ?disableDefaultAllChildrenSearch: bool,
        ?portalTermSelectArea: IRefValue<option<HTMLElement>>,
        ?fullwidth: bool, ?autoFocus: bool,
        ?classNames: TermSearchStyle
    ) =

would normally become:

export function TermSearch(termSearchInputProps: any): ReactElement {

with my changes will become:

export function TermSearch(termSearchInputProps: { onTermSelect: ((arg0: Option<Term>) => void), term?: Term, parentId?: string, termSearchQueries?: [string, ((arg0: string) => Promise<Term[]>)][], parentSearchQueries?: [string, ((arg0: [string, string]) => Promise<Term[]>)][], allChildrenSearchQueries?: [string, ((arg0: string) => Promise<Term[]>)][], advancedSearch?: { form: ((arg0: { cancel: (() => void), startSearch: (() => void) }) => ReactElement), search: (() => Promise<Term[]>) } | boolean, onFocus?: (() => Promise<void>), onBlur?: (() => Promise<void>), onKeyDown?: ((arg0: KeyboardEvent) => Promise<void>), showDetails?: boolean, debug?: boolean, disableDefaultSearch?: boolean, disableDefaultParentSearch?: boolean, disableDefaultAllChildrenSearch?: boolean, portalTermSelectArea?: IRefValue$1<Option<HTMLElement>>, fullwidth?: boolean, autoFocus?: boolean, classNames?: TermSearchStyle }): ReactElement {

let me know what you think @MangelMaxime @Zaid-Ajaj . I would really appreciate this change 🙂

[MangelMaxime]

Generated code seems ok to me