Inspect updating of current alias

[kulla]

I have got the message, that certain aliases do not get updated properly. Affected URL examples:

• https://es.serlo.org/matem%C3%A1ticas/n%C3%BAmeros-y-medidas/fracciones-y-n%C3%BAmeros-decimales/fracciones
• https://de.serlo.org/community/sandkasten/planetarische-leitplanken

[kulla]

#478 as a follow up why the alias in https://de.serlo.org/community/sandkasten/planetarische-leitplanken is wrong...