Add platformStatic to Charsets values.

libraries/stdlib/src/kotlin/text/CharsetsJVM.kt

@@ -12,33 +12,38 @@ public object Charsets {
     /**
      * Eight-bit UCS Transformation Format
      */
-    // TODO: KT-5766 Cannot compile function with optional parameters with platformStatic value
+    platformStatic
     public val UTF_8: Charset = Charset.forName("UTF-8")
 
     /**
      * Sixteen-bit UCS Transformation Format, byte order identified by an
      * optional byte-order mark
      */
+    platformStatic
     public val UTF_16: Charset = Charset.forName("UTF-16")
 
     /**
      * Sixteen-bit UCS Transformation Format, big-endian byte order
      */
+    platformStatic
     public val UTF_16BE: Charset = Charset.forName("UTF-16BE")
 
     /**
      * Sixteen-bit UCS Transformation Format, little-endian byte order
      */
+    platformStatic
     public val UTF_16LE: Charset = Charset.forName("UTF-16LE")
 
     /**
      * Seven-bit ASCII, a.k.a. ISO646-US, a.k.a. the Basic Latin block of the
      * Unicode character set
      */
+    platformStatic
     public val US_ASCII: Charset = Charset.forName("US-ASCII")
 
     /**
      * ISO Latin Alphabet No. 1, a.k.a. ISO-LATIN-1
      */
+    platformStatic
     public val ISO_8859_1: Charset = Charset.forName("ISO-8859-1")
 }