Add tablet buttons to `InputKey` enumeration
Add tablet buttons to `InputKey` enumeration

ZLima12/osu-framework,peppy/osu-framework,peppy/osu-framework,ppy/osu-framework,ZLima12/osu-framework,ppy/osu-framework,ppy/osu-framework,smoogipooo/osu-framework,peppy/osu-framework,smoogipooo/osu-framework