fix repeat and some other minor issues

[bkamins]

Some fixes after JuliaLang/julia#31829.
Mainly restricting the signature of repeat.

Additionally one dangling get to unwrap for CategoricalArrays.jl compatibility I missed earlier.

@mbauman

The JuliaLang/julia#31829 broke the following thing in Julia Base that was not covered by tests (fortunately we had appropriate tests in DataFrames.jl):

julia> x = [1,2,3]
3-element Vector{Int64}:
 1
 2
 3

julia> repeat(x, inner=1,outer=1)
3-element Vector{Int64}:
 1
 2
 3

julia> repeat(x, inner=1,outer=false) # it works but I think it should be an error
Int64[]

julia> repeat(x, inner=false,outer=1) # previously it worked
ERROR: ArgumentError: invalid index: false of type Bool

[bkamins]

Actually maybe Bool in repeat should be allowed as it is not an indexing context and it is clear what will be the result of the operation. Let us wait what @mbauman comments for Julia Base.

[bkamins]

As commented above - I have thought about it and I think that we should accept Bool as in this context it should be treated as Integer.

[nalimilan]

And what happens before 1.6? :-)

[bkamins]

Before (and including 1.6) 1.7 it works - see the old test that got removed.

[nalimilan]

I mean, shouldn't this be tested too?

[bkamins]

OK - I have reverted it (although it was kept mainly to keep track of the bug in Julia Base).

A follow up PR in Julia Base that should be fixed is JuliaLang/julia#39962 (I am pinging you as it seem no one commented on it).