Language-specific user dictionaries (en-US, de-DE, etc.)
have got a new "Grammar By" field to specify
optional automatic affixation and compounding of the
new words by adding an example dictionary word.

Test example:

Create an en-US user dictionary. Add the new word
"crowdfund" to it, also an example, the Hunspell
en-US dictionary word "fund" in the optional
"Grammar By" field.

This way, the word "crowdfund" will be recognized
by the spell checker with suffixes of the word "fund",
too: crowdfund’s, crowdfunds, crowdfunder, crowdfunders
and crowdfunding.

Hunspell dictionaries with compound flag usage (German,
Hungarian, etc.) can support automatic compounding of
the new words, too.

Change-Id: Id70dbee4544643967153f730ae64938e5cee0c82
Reviewed-on: https://gerrit.libreoffice.org/44562Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: László Németh <nemeth@numbertext.org>