Improve the docs and behavior around infinite retries

[martintmk]

Details on the issue fix or feature implementation

• Using int.MaxValue will indicate infinite retries to retry strategy.
• Docs improvements.

Closes #944

Confirm the following

• I started this PR by branching from the head of the default branch
• I have targeted the PR to merge into the default branch
• I have included unit tests for the issue/feature
• I have successfully run a local build

[codecov]

Codecov Report

Patch coverage: 100.00% and project coverage change: +0.01% 🎉

Comparison is base (2ef9ae0) 83.92% compared to head (3724183) 83.93%.
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1574      +/-   ##
==========================================
+ Coverage   83.92%   83.93%   +0.01%     
==========================================
  Files         279      279              
  Lines        6520     6525       +5     
  Branches     1017     1019       +2     
==========================================
+ Hits         5472     5477       +5     
  Misses        839      839              
  Partials      209      209              

Flag	Coverage Δ
linux	?
macos	83.93% <100.00%> (+0.01%)	⬆️
windows	83.93% <100.00%> (+0.01%)	⬆️

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Files Changed	Coverage Δ
...c/Polly.Core/Retry/RetryStrategyOptions.TResult.cs	100.00% <ø> (ø)
src/Polly.Core/Retry/RetryResilienceStrategy.cs	100.00% <100.00%> (ø)

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