encoder: Encode instances of Number as numbers, not maps

[FlorianDenis]

Make sure instances of Number as encoded as a number instead of a map.
I am encountering this issue in my current project, I believe this is a more sensible default behavior

All tests pass.

[codecov-commenter]

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Codecov Report

Attention: Patch coverage is 50.00000% with 1 line in your changes missing coverage. Please review.

Project coverage is 97.19%. Comparing base (59057ee) to head (b450e25).
Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
src/Encoder.ts	50.00%	1 Missing ⚠️

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Additional details and impacted files

@@            Coverage Diff             @@
##             main     #271      +/-   ##
==========================================
- Coverage   97.28%   97.19%   -0.09%     
==========================================
  Files          17       17              
  Lines        1140     1142       +2     
  Branches      253      254       +1     
==========================================
+ Hits         1109     1110       +1     
- Misses         31       32       +1     

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[gfx]

Why do you use the Number wrapper object? There's no reason to use it and it seems just a bug, in your project.

[FlorianDenis]

I am not going to go too much into the details of my project because this is not the place, but it turns out that I have a need for representing a integer using an object instance rather than a primitive type, a need which Number was built into the language to fulfill. This is a deliberate choice, not a bug.

My goal with this PR is merely to point out that Number does exist today as a core part of the language (has since ES1, really), and so the question this poses here is:

• Do we consider the MessagePack representation of it should be a map
• Or do we consider it should be a int/float?

[FlorianDenis]

@gfx Any thoughts on the above?