string.find annotation of return value is not precise enough #2179
Description
From Lua Reference Manual https://www.lua.org/manual/5.3/manual.html#pdf-string.find
Return value is {start, end} or nil (when not found). It is better to add question mark to annotation of return value for all 5.1-5.4 (including JIT).
Existing annotation in LuaLangServer 3.6.22 is misleading: developers think that in case when pattern or substring is not found string.find returns -1.