Fix julia 1.6 tests

[fonsp]

This fixes some test failures from future Julia API introduced in #16

It looks like the inferrability tests is still breaking, I traced it back to this line:

FuzzyCompletions.jl/src/FuzzyCompletions.jl

Line 628 in 1476500

return complete_any_methods(ex_org, callee_module::Module, context_module, moreargs, shift), (0:length(rexm.captures[1])+1) .+ rexm.offset, false

If you uncomment it then the inference test passes, I don't know how to fix it.

[pfitzseb]

Let's just disable the inference tests on 1.6?

[fonsp]

good idea!