Add document: Keyboard Preferences pane

Number:rdar://39295951 Date Originated:2018/4/10
Status:Duplicate/35168135 Resolved:
Product:macOS + SDK Product Version:Keyboards, mice and trackpads
Classification: Reproducible:
Default bundled input methods show preferences pane within System Preferences.

Although most input methods need some configurations(e.g. base keyboard layout, punctuation style, ...), there are no standard way to show configuration page.

To provide a consistent user expericen, it is good to allow 3rd party input methods to use preferences pane.

Steps to Reproduce:

Expected Results:
Add documentation for preferences pane of input method. 

Actual Results:
Such document is not exist.

I added `Preferences.perfPane` my into input method, and it is loaded and displayed from System Preferences.

macOS High Sierra / 10.13.4 (17E199)



Please note: Reports posted here will not necessarily be seen by Apple. All problems should be submitted at before they are posted here. Please only post information for Radars that you have filed yourself, and please do not include Apple confidential information in your posts. Thank you!