Fix a bug in pathname processing in SFTP client symlink request

This commit fixes the processing of path name arguments in the
SFTPClient symlink method. Path normalization was previously being done
on the wrong argument. Thanks go to André Glüpker for reporting the
problem and providing test code to demonstrate it!

asyncssh/sftp.py

@@ -5329,8 +5329,8 @@ async def symlink(self, oldpath: _SFTPPath, newpath: _SFTPPath) -> None:
 
         """
 
-        oldpath = self.compose_path(oldpath)
-        newpath = self.encode(newpath)
+        oldpath = self.encode(oldpath)
+        newpath = self.compose_path(newpath)
         await self._handler.symlink(oldpath, newpath)
 
     async def link(self, oldpath: _SFTPPath, newpath: _SFTPPath) -> None: