xfd: cfd rename garbles "target category" when there's periods in the target category title

[NovemLinguae]

Reported by Paradoctor at https://en.wikipedia.org/wiki/Wikipedia_talk:Twinkle#Target_field_not_correctly_processed_in_CfD_request

Target category Category:Road to ... (Family Guy) gets garbled by Twinkle to Road to ..