lib.Result.__repr__(): Fix binary stdout exception

__repr__() tries to decode binary stdout as string and fails without a backup. Fix that.
Signed-off-by: Jan Lindemann <jan@janware.com>

src/python/jw/pkg/lib/Result.py

@@ -44,7 +44,12 @@ class Result:
         if self.__stdout is None:
             ret = ''
         else:
-            ret = self.stdout_str[:20]
+            max_len = 40
+            try:
+                ret = self.stdout_str[:max_len]
+            except UnicodeDecodeError:
+                chunk = self.__stdout[:max_len]
+                ret = ''.join(chr(b) if 32 <= b <= 126 else '.' for b in chunk)
         if quote:
             ret = f'"{ret}"'
         return ret