Avoid capturing where possible.

[IEvangelist]

The issue or feature being addressed

All of these changes are only within the Docs/Snippets content.

When reviewing docs, I noticed that some of the example snippets were lifting (capturing outer scope variables) when it clearly wasn't intended as the state parameter was passed an argument with the same name. Ideally, we shouldn't be capturing outer scope variables when using the state parameter.

Details on the issue fix or feature implementation

In this PR:

• Some cases are simply resolved by adding the static modifier.
• Other cases involved renaming the delegate parameter for the inner scope to isolate the variable usage.
• And a few cases required passing state.

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

[martintmk]

Please also run dotnet mdsnippets from the Polly root to update the relevant docs.

[codecov]

Codecov Report

Patch and project coverage have no change.

Comparison is base (8241fc4) 84.63% compared to head (bfe49e4) 84.63%.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1609   +/-   ##
=======================================
  Coverage   84.63%   84.63%           
=======================================
  Files         306      306           
  Lines        6820     6820           
  Branches     1044     1044           
=======================================
  Hits         5772     5772           
  Misses        839      839           
  Partials      209      209           

Flag	Coverage Δ
linux	84.63% <ø> (ø)
macos	84.63% <ø> (ø)

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