Float32 edge cases of leading/trailing 0 in floating points

[nickrobinson251]

Current behaviour is

julia> str = """
       x = 3.f0
       y = 3f0
       """;

julia> print(format_text(str))
x = 3.f0
y = 3f0

I think the desired behaviour (following #61 and #83) is to output like the repl:

julia> 3.f0
3.0f0

julia> 3f0
3.0f0

julia> 30f0
30.0f0