Fix class and method signatures in typings

[yuna0x0]

Description

The TypeScript type declaration file has various errors, which makes the library unusable under TypeScript.

Inconsistent letter case:

• Usage in code comment differ from those in the docs.
• Class name letter case not matching the source code.
• Using non-primitive boxed objects instead of primitive types (ref)

Typo:

• getBirthdayCharacter() -> getBirthdayCharacters()

Missing or incorrect arguments:

-update(options: UserOptions): Promise<UserProfileOptions>;
update(options: UserOptionsInput): Promise<UserProfileOptions>;

-getBirthdayCharacter(page: number): Promise<PersonRelation[]>;
getBirthdayCharacters(page?: number): Promise<PersonRelation[]>;

-getBirthdayStaff(page: number): Promise<PersonRelation[]>;
getBirthdayStaff(page?: number): Promise<PersonRelation[]>;

-postText(text: string, id?:number): Promise<TextActivity>;
postText(text: string, id: number | null): Promise<TextActivity>;

-postMessage(text: string, recipientId: number, isPrivate?:boolean, id?: number): Promise<MessageActivity>;
postMessage(text: string, recipientId: number, isPrivate?:boolean, id: number | null): Promise<MessageActivity>;

-getList(mediaID: Number)
getList(mediaID: number, page?: number, perPage?: number)

-getComments(id: number, page: number, perPage: number)
getComments(id: number, page?: number, perPage?: number)