zlib: fix zstd reset

[jasnell]

Handful of additional bits I noticed while poking around zstd..

• Preserve dictionaries and params when zstd is reset.
• Update missing documentation.
• Reject invalid dictionaries (they would previously no-op)

The rejection is technically a behavior change but zstd is still experimental.

[codecov]

Codecov Report

❌ Patch coverage is 54.54545% with 15 lines in your changes missing coverage. Please review.
✅ Project coverage is 90.20%. Comparing base (8af7545) to head (5c17be7).
⚠️ Report is 21 commits behind head on main.

Files with missing lines	Patch %	Lines
src/node_zlib.cc	46.42%	11 Missing and 4 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #65867      +/-   ##
==========================================
+ Coverage   90.18%   90.20%   +0.01%     
==========================================
  Files         771      771              
  Lines      264619   264660      +41     
  Branches    50231    50246      +15     
==========================================
+ Hits       238653   238736      +83     
+ Misses      16961    16918      -43     
- Partials     9005     9006       +1     

Files with missing lines	Coverage Δ
lib/zlib.js	98.41% <100.00%> (+0.27%)	⬆️
src/node_zlib.cc	79.00% <46.42%> (-0.19%)	⬇️

... and 32 files with indirect coverage changes

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