docs: add link about Nanosecond precision to usage page

[bednar]

Closes #314

Proposed Changes

Added link about Nanosecond precision to usage page:

Checklist

• Rebased/mergeable
• pytest tests completes successfully
• Commit messages are in semantic format
• Sign CLA (if not already signed)

[codecov-commenter]

Codecov Report

Merging #315 (3ddee4f) into master (37d3598) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #315   +/-   ##
=======================================
  Coverage   92.55%   92.55%           
=======================================
  Files          27       27           
  Lines        2204     2204           
=======================================
  Hits         2040     2040           
  Misses        164      164           

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