[luatex] stability disclaimer in the manual

[Manuel Pégourié-Gonnard]

Hi,

I happened to re-read the disclaimer in the introduction of the LuaTeX manual
(version from trunk) recently. At the end, it states that

> Currently we expect the first release with (some) fixed interfaces to be
> available sometime in the autumn of 2008. [...]

Since 2008 is now in the past, you may want to update the wording :-)

Manuel.

PS: I'm not asking for more stability right now, nor for comprehensive
stability-related indications in the manual, just pointing out a small typo.