Docs: copy edits for cardinality measurement guide

[grafsean]

Copy edits for Mario's #1611

[github-actions]

🚫 [doc-validator] _{reported by reviewdog 🐶}
The anchor 'example-of-calculation' does not exist in the file 'docs/sources/cardinality.md'.
Replace the anchor with one of the available anchors.

Available anchors are: "beyla-metrics-cardinality, terminology, process-level-metrics, application-level-metrics, example-calculation, network-level-metrics, service-graph-metrics, span-metrics, case-study-cardinality-of-opentelemetry-demo, measure-process-level-metrics, measure-application-level-metrics, measure-network-level-metrics, measure-service-graph-metrics, measure-span-metrics"

[github-actions]

Hello @grafsean!
Backport pull requests need to be either:

• Pull requests which address bugs,
• Urgent fixes which need product approval, in order to get merged,
• Docs changes.

Please, if the current pull request addresses a bug fix, label it with the type/bug label.
If it already has the product approval, please add the product-approved label. For docs changes, please add the type/docs label.
If the pull request modifies CI behaviour, please add the type/ci label.
If none of the above applies, please consider removing the backport label and target the next major/minor release.
Thanks!

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 71.13%. Comparing base (cdb8a7c) to head (3008ce4).
Report is 12 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1622      +/-   ##
==========================================
- Coverage   71.15%   71.13%   -0.02%     
==========================================
  Files         197      197              
  Lines       19871    19881      +10     
==========================================
+ Hits        14139    14143       +4     
- Misses       5055     5059       +4     
- Partials      677      679       +2     

Flag	Coverage Δ
integration-test	52.85% <ø> (+0.36%)	⬆️
k8s-integration-test	53.13% <ø> (-0.08%)	⬇️
oats-test	34.69% <ø> (+0.02%)	⬆️
unittests	47.03% <ø> (-0.03%)	⬇️

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[mariomac]

Thanks!