pspp: Small typo in polish name which breaks sed during build

[Friedrich Beckmann]

Cześć polish translation team,

thank you very much for all your translations! Could you maybe fix the following
small typo in the polish translation of the pspp project:

https://git.savannah.gnu.org/cgit/pspp.git/commit/?id=57a6e611f43bfb0ef492b28200de5071a79ce21e

which breaks the build of pspp on MacOS? If I fix this in the source code data 
it will always
be overwritten by the file from the translation project. The pspp project:

https://translationproject.org/domain/pspp.html

Thanks for your help!

Friedrich