Fix newlines around nested dicts

[ettersi]

On current master:

julia> TOML.print(Dict("a" => Dict("b" => Dict("c" => 1)), "d" => Dict("e" => 2)))

[a.b]
c = 1
[d]
e = 2

With this PR:

julia> TOML.print(Dict("a" => Dict("b" => Dict("c" => 1)), "d" => Dict("e" => 2)))
[a.b]
c = 1

[d]
e = 2

[codecov]

Codecov Report

Merging #48 (e04d29d) into master (44aab3c) will increase coverage by 0.06%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master      #48      +/-   ##
==========================================
+ Coverage   93.21%   93.27%   +0.06%     
==========================================
  Files           3        3              
  Lines         707      714       +7     
==========================================
+ Hits          659      666       +7     
  Misses         48       48              

Impacted Files	Coverage Δ
src/print.jl	94.01% <100.00%> (ø)
src/TOML.jl	100.00% <0.00%> (ø)
src/parser.jl	92.96% <0.00%> (+0.06%)	⬆️

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.