doc: variabilized various metrics in docs using codegen counts.

[fredbi]

Motivation: the documentation site is peppered with counts of methods,
assertion etc. Now these are maintained automatically using a generated
hugo parameters file.

doc: added a generated quick index table.

This table displays all assertions with their logical opposite (complementary assertion) in compact form.

• evolved codegen to produce this table, using the new "opposite" comment annotation
• added notes relative to the confusing Decreasing/NonDecreasing pairs, with additional tests to relieve any doubt on these being complementary
• regenerated all code for go doc update

Change type

Please select: 🆕 New feature or enhancement|🔧 Bug fix'|📃 Documentation update

Short description

Fixes

Full description

Checklist

• I have signed all my commits with my name and email (see DCO. This does not require a PGP-signed commit
• I have rebased and squashed my work, so only one commit remains
• I have added tests to cover my changes.
• I have properly enriched go doc comments in code.
• I have properly documented any breaking change.

[codecov]

Codecov Report

❌ Patch coverage is 88.65979% with 11 lines in your changes missing coverage. Please review.
✅ Project coverage is 91.31%. Comparing base (ac2dada) to head (19e5daf).
⚠️ Report is 1 commits behind head on master.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
codegen/internal/generator/doc_generator.go	87.20%	6 Missing and 5 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master      #97      +/-   ##
==========================================
- Coverage   91.33%   91.31%   -0.03%     
==========================================
  Files          94       94              
  Lines       12128    12222      +94     
==========================================
+ Hits        11077    11160      +83     
- Misses        835      841       +6     
- Partials      216      221       +5     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.