zig fmt can remove comments

[Srekel]

Minimal repro case: Open a new file, fmttest.zig for example, add the following two lines of code:

/// test
// test

Format it using zig fmt. Afterwards, there's only a single blank line left.

Tested on Windows using zig-windows-x86_64-0.5.0+d18b5f8b5.zip

[Vexu]

I have this solved for both variations of top-level doc comments I presented here. Alternatively adding a compile error for unattached doc comment would be quite easy if we don't want top-level doc comments.