Logical indexing: Better error when Bool array index is wrong size

[BioTurboNick]

Currently (1.5.3) if you try to access an array with a logical test of the wrong size, the error is:

[1;2;3][[true, false]]
ERROR: BoundsError: attempt to access 3-element Array{Int64,1} at index [Bool[1, 0]]

For small arrays, this may be clear enough. For larger arrays, much less clear.

Suggest something like:

ERROR: BoundsError: attempt to access 3-element Array{Int64,1} with mismatched Bool array of length 2.

I'm willing to do the PR if that seems okay.

[mbauman]

This has recently changed on master:

julia> [1;2;3][[true, false]]
ERROR: BoundsError: attempt to access 3-element Vector{Int64} at index [2-element Vector{Bool}]

This was #38689.