Add BGN examples for Pashto `bgnpcgn-pus-Arab-Latn-1968`

[ronaldtse]

Add BGN Dari transliteration examples. This applies to the system:
bgnpcgn-pus-Arab-Latn-1968

Examples available here:
https://github.com/interscript/interscript-private-references/blob/master/bgn/ara-dari-pashto-turkic-samples.xlsx

[AhMohsen46]

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