Improve usability of ResilienceStrategy<T>

[martintmk]

Details on the issue fix or feature implementation

These changes enable flowing the type used in the callback back to the result:

ResilienceStrategy<object> strategy = NullResilienceStrategy<object>.Instance;

int v1 = strategy.Execute(() => 10);
string v2 = strategy.Execute(() => "val");
bool v3 = strategy.Execute(() => true);

Previously, these all would be object:

ResilienceStrategy<object> strategy = NullResilienceStrategy<object>.Instance;

object v1 = strategy.Execute(() => 10);
object v2 = strategy.Execute(() => "val");
object v3 = strategy.Execute(() => true);

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

[martincostello]

Just not a big fan of the name T as it's not very descriptive alongside TResult and TState and might cause some confusion between T and TResult when both are kinda a result (just in different contexts).

[martincostello]

I wonder if there's a better name we can give this rather than T?

[martintmk]

Any suggestions?

[martintmk]

Maybe just swap T with TResult?

So it will be ResilienceStrategy<T> but individual methods will have TResult?

[martincostello]

I didn't have any good suggestions - your one sounds fine to me.

[codecov]

Codecov Report

Merging #1428 (c1b803e) into main (59e461a) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main    #1428   +/-   ##
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  Coverage   83.92%   83.92%           
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  Files         275      275           
  Lines        6526     6526           
  Branches     1007     1007           
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  Hits         5477     5477           
  Misses        840      840           
  Partials      209      209           

Flag	Coverage Δ
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windows	83.92% <ø> (ø)

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Files Changed	Coverage Δ
src/Polly.Core/ResilienceStrategy.TResult.Async.cs	100.00% <ø> (ø)
src/Polly.Core/ResilienceStrategy.TResult.Sync.cs	100.00% <ø> (ø)