code layout improvements

[bkamins]

I wanted to fix this problems in error printing (missing space in both cases):

julia> df = DataFrame(a=1)
1×1 DataFrame
 Row │ a     
     │ Int64 
─────┼───────
   1 │     1

julia> push!(df, (a=1, b=2))
ERROR: ArgumentError: `push!` with `cols` equal to `:setequal`requires `row` to have the same number of elements as the number of columns in `df`.

julia> dfv = @view df[:, :]
1×1 SubDataFrame
 Row │ a     
     │ Int64 
─────┼───────
   1 │     1

julia> dfv.x = [1]
ERROR: ArgumentError: Replacing or adding of columns of a SubDataFrame is not allowed.Instead use `df[:, col_ind] = v` or `df[:, col_ind] .= v` to perform an in-place assignment.

So I also reviewed the whole source code to make sure that we always use a space at the end of the line when we break it.

• I changed very long lines in isapprox.

This PR does not change anything from the functionality perspective.

[bkamins]

@nalimilan - only coverage fails.

[bkamins]

Thank you!