Replace the String producing Display logic to using a Formatter

[hansl]

This code heavily relied on allocating strings and vectors of strings for each object properties. This new logic eliminates the allocations entirely, saving both memory and improving performance.

It also makes the logic easier to follow, which might be help with simplification later.

Tests should be unchanged.

[codecov]

Codecov Report

❌ Patch coverage is 63.15789% with 42 lines in your changes missing coverage. Please review.
✅ Project coverage is 50.27%. Comparing base (6ddc2b4) to head (a7389c7).
⚠️ Report is 517 commits behind head on main.

Files with missing lines	Patch %	Lines
core/engine/src/value/display.rs	63.15%	42 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4393      +/-   ##
==========================================
+ Coverage   47.24%   50.27%   +3.03%     
==========================================
  Files         476      508      +32     
  Lines       46892    51144    +4252     
==========================================
+ Hits        22154    25714    +3560     
- Misses      24738    25430     +692     

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[hansl]

Not sure how much console logging is done in the benchmark tests, but I did notice a noticeable (reproduced twice, but within noise) increase in performance:

Before PR

PROGRESS Richards
RESULT Richards 174
PROGRESS DeltaBlue
RESULT DeltaBlue 194
PROGRESS Encrypt
PROGRESS Decrypt
RESULT Crypto 161
PROGRESS RayTrace
RESULT RayTrace 439
PROGRESS Earley
PROGRESS Boyer
RESULT EarleyBoyer 530
PROGRESS RegExp
RESULT RegExp 85.7
PROGRESS Splay
RESULT Splay 809
PROGRESS NavierStokes
RESULT NavierStokes 358
SCORE 274

With PR

PROGRESS Richards
RESULT Richards 179
PROGRESS DeltaBlue
RESULT DeltaBlue 196
PROGRESS Encrypt
PROGRESS Decrypt
RESULT Crypto 167
PROGRESS RayTrace
RESULT RayTrace 445
PROGRESS Earley
PROGRESS Boyer
RESULT EarleyBoyer 538
PROGRESS RegExp
RESULT RegExp 85.0
PROGRESS Splay
RESULT Splay 796
PROGRESS NavierStokes
RESULT NavierStokes 365
SCORE 277

[nekevss]

Have you seen the writeable crate by chance?

[hansl]

@nekevss I had not, let me see if it helps push performance further.

[hansl]

@nekevss I didn't see performance improvements (even saw minor regression). I cannot inspect values and guess the size of output as I need a context, so I don't see any theoretical gains from using writeable.