Add pretty print to hexdump

[JSCU-CNI]

This PR aims to provide a stub for pretty colors as described in #80. Currently only null bytes are 'greyed-out' and ASCII printable characters are whitened.

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Perhaps we can look at some of these resources to determine what other coloring rules we would like to apply here:

• https://simonomi.dev/blog/color-code-your-bytes/
• http://thestone.zone/hacking/2019/01/01/hacking-quest-for-glory.html

Some things that come to mind:

• Should we show difference between certain printable ASCII characters (letters, numbers, capitalization, etc.)?
• Should we color white space characters (0x09-0x0D, 0x20, etc.)?
• What about non-ASCII (0x80-0xFF)?

The current implementation does not change the default behavior of hexdump, using the pretty argument is required.

[yunzheng]

Nice! I’m a pretty big fan of HexFiend on macOS which also added hex coloring based on hexyl, see this PR:

HexFiend/HexFiend#181

Think if we base the coloring rules and scheme on that it would already be very nice.

[JSCU-CNI]

Think if we base the coloring rules and scheme on that it would already be very nice.

Thanks for the input @yunzheng, I have applied some rules from HexFriend in 9fa9977. I feel the white color of printable ASCII is somewhat calmer to read than a blue color. What do you think? Perhaps we could make this user customizable in the future, but for simplicity's sake for now I think we should settle on one coloring scheme.

For example, a small PE file is now rendered like this:

[yunzheng]

That looks awesome, yes looking at the Hexyl example I think the white is much better on the eyes!

[codecov]

Codecov Report

❌ Patch coverage is 0% with 48 lines in your changes missing coverage. Please review.
✅ Project coverage is 0.00%. Comparing base (edf9f8e) to head (40f71db).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
dissect/cstruct/utils.py	0.00%	48 Missing ⚠️

Additional details and impacted files

@@          Coverage Diff          @@
##            main    #155   +/-   ##
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  Coverage   0.00%   0.00%           
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  Files         21      21           
  Lines       2438    2470   +32     
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- Misses      2438    2470   +32     

Flag	Coverage Δ
unittests	0.00% <0.00%> (ø)

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[codspeed-hq]

Merging this PR will not alter performance

✅ 12 untouched benchmarks

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_{Comparing JSCU-CNI:pretty-hexdump (40f71db) with main (edf9f8e)}