README: Creating Notifications section outdated

[Chealer]

The README's Creating Notifications section contains a table with method signatures like the following: success(title: any, content?: any, override?: any, context?: any)

At least the first 7 entries are outdated, as the title argument is now optional. Additionally, a set(notification: Notification, to: boolean): Notification method is not documented.

By the way:

1. "This are the currently available access methods:" should read "These are the currently available access methods:".
2. Most descriptions refer to "the provided title and content", when providing both is in fact optional.