Change mui autonym according to Ethnologue

This language was added long ago when mui and plm
were separate codes, and mui was "Musi" and plm
was "Palembang". The code plm was retired in 2008
and the only valid code now is mui, and its autonym
according to Ethnologue is "Baso Palembang".
This is also the name most commonly used by the
language's speakers according to the article
Alsamadani, Mardheya; Taibah, Samar (2019).
"Types and Functions of Reduplication in Palembang".
Journal of the Southeast Asian Linguistics Society.

data/language-data.json

@@ -3045,7 +3045,7 @@
             [
                 "AS"
             ],
-            "Musi"
+            "Baso Palembang"
         ],
         "mus": [
             "Latn",