Autocomplete: PrefixCompleter adds unwanted SPACE ' ' (ASCII 32) to each string

[carli2]

If I press Tab and the string is completed, the completer adds a unwanted space character to the output. I workarounded it by adding each option twice with different postfix, but this is very hacky since the completer then tries to add one of the two postfixes.

Is there a proper way to prevent the completer from adding a space to the end of line?