Remove max value references

[HaleySchuhl]

Describe your changes
Remove references to the deprecated max_value parameter throughout doc pages.

Type of update
Is this a:

• Update to documentation

Associated issues
#1304

Additional context
Add any other context about the problem here.

For the reviewer
See this page for instructions on how to review the pull request.

• PR functionality reviewed in a Jupyter Notebook
• All tests pass
• Test coverage remains 100%
• Documentation tested
• New documentation pages added to plantcv/mkdocs.yml
• Changes to function input/output signatures added to updating.md
• Code reviewed
• PR approved

[codecov]

Codecov Report

Merging #1314 (381cf6f) into release-4.0 (70a3c24) will not change coverage.
Report is 1 commits behind head on release-4.0.
The diff coverage is n/a.

@@              Coverage Diff              @@
##           release-4.0     #1314   +/-   ##
=============================================
  Coverage       100.00%   100.00%           
=============================================
  Files              157       157           
  Lines             6759      6758    -1     
=============================================
- Hits              6759      6758    -1     

Flag	Coverage Δ
unittests	100.00% <ø> (ø)

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see 1 file with indirect coverage changes