Allow encoding standard strings

Author: florianpircher

Sources/OpenStepPropertyList/PropertyList Encoding.swift

@@ -52,7 +52,7 @@ extension PropertyList {
 		switch self {
 		case .string(let byteString, options: let options):
 			Self.encodeString(
-				byteString,
+				byteString.value,
 				to: &buffer,
 				prefersUnquoted: options.contains(.unquoted),
 				lineFeedEscaping: options.lineFeedEscaping,
@@ -87,21 +87,21 @@ extension PropertyList {
 
 	@inlinable
 	public static func encodeString(
-		_ byteString: ByteString,
+		_ string: String,
 		to buffer: inout EncodingBuffer,
 		prefersUnquoted: Bool,
 		lineFeedEscaping: PropertyList.StringOptions.LineFeedEscaping?,
 		escapedHorizontalTabsOctal: Bool,
 	) {
-		let isUnquoted = prefersUnquoted && !byteString.isEmpty && byteString.utf8.allSatisfy(PropertyList.isUnquotedStringCharacter(codePoint:))
+		let isUnquoted = prefersUnquoted && !string.isEmpty && string.utf8.allSatisfy(PropertyList.isUnquotedStringCharacter(codePoint:))
 
 		if isUnquoted {
-			buffer.append(contentsOf: byteString.utf8)
+			buffer.append(contentsOf: string.utf8)
 		}
 		else {
 			buffer.append(UInt8(ascii: "\""))
 
-			var iterator = byteString.utf8.makeIterator()
+			var iterator = string.utf8.makeIterator()
 
 			func writeLineFeed() {
 				switch lineFeedEscaping {
@@ -317,7 +317,7 @@ extension PropertyList {
 			}
 
 			self.encodeString(
-				key.string,
+				key.string.value,
 				to: &buffer,
 				prefersUnquoted: key.options.contains(.unquoted),
 				lineFeedEscaping: key.options.lineFeedEscaping,