Spellchecking dictionaries in LyX 2.4 installer

[Yuriy Skalko]

> Good that means careful user can get whatever dictionary he wants.
> Anyway, I don't see any problem adding the languages you proposed.
> 
> Pavel

I don't want to say that current installation process is not so good. 
Just want to simplify life for not so careful users.


P.S. Just now checked the UserGuide manual. It is linking to SourceForge 
as dictionary repository. Should we update these links?


Yuriy