[Gimp-docs] Key references

[julien]

po files are translated for de fr it... but key-reference.xml is built
for 'en' only
and the key references don't appear in html index.

I translated key-reference.xml and saved it as key-reference-fr.xml. I
added a
<xi:include... for it in gimp.xml. So I have now the key references in
the HTML index.

Key references are stable. Why build key-reference.xml every time?
May I commit key-reference-fr?

Julien