Minor old-standing documentation nitpick

[Sergey Zakharchenko <doublef.mobile@...>]

Hello list,

For a long time, "string.find (s, pattern [, init [, plain]])"
documentation reads:
"Note that if plain is given, then init must be given as well." This
is a bit surprising since a lot of other functions, like
[table.]unpack, or load, or utf8.* ones, have several optional
arguments but don't have similar notices; one would think that it says
init must be non-nil but init can be supplied as nil quite all right
in such cases:

> =string.find("xyz","y",nil,true)
2       2

That notice could as well be dropped...

Best regards,

-- 
DoubleF