Persian calendar months and years problem.

Nobody has claimed this yet.

This issue #1077 was posted and based on #1080 and [this](https://github.com/spiegelp/MaterialDesignInXamlToolkit/tree/CalendarSupport) problem should be solved, but it was not. there are Calendar header translated to persian calendar but Calendar body is Gregorian yet. I set the Language property as persian and Flow direction as RightToLeft but not effected on result, add startup codes also.

see: [this screenshot](https://www.dropbox.com/s/4v7q3pglmyouo11/Untitled.png?dl=0)

Pay attention to screenshot Red zone are persian but Yellow zone is Gregorian.
On Yellow zone year is 1398 and day is "پنجشنبه 17 بهمن" is 17/11/1398, but calendar day is 6/2/2020.

also on below screenshot applies for months and years, 2020 must be 1398.

https://www.dropbox.com/h?preview=Untitled.pngq.png

No source file or test is identified; first reproduce the calendar with Language set to Persian and FlowDirection set to RightToLeft, using the reported screenshots and startup-code context. Done means the calendar body, months, years, and day values use the Persian calendar consistently instead of showing Gregorian dates.

Written by the indexing model from the issue text.