Applied the newer code analysis rules.

[jscarle]

Starting with .NET 5, there are new code analysis rules being shipped with each release of the .NET SDK.

Since they're mostly straightforward fixes, I addressed the following rules:

• CA1002: Do not expose generic lists
• CA1062: Validate arguments of public methods
• CA1859: Use concrete types when possible for improved performance
• CA1852: Seal internal types
• CA1860: Avoid using 'Enumerable.Any()' extension method
• CA2007: Do not directly await a Task

Due to the nature of the project, some rules wouldn't make sense, therefore I muted the following rules:

• CA1031: Do not catch general exception types
• CA1040: Avoid empty interfaces
• CA1307: Specify StringComparison for clarity
• CA1711: Identifiers should not have incorrect suffix
• CA1716: Identifiers should not match keywords
• CA1812: Avoid uninstantiated internal classes

I also did a minor cleanup of small warnings. Each step was done as a separate commit to facilitate the code review.

[github-actions[bot]]

This PR is stale because it has been open 28 days with no activity. Remove stale label or comment or this will be closed in 14 days.

[jscarle]

@jbogard Can you take a look a this when you have a moment?

[github-actions[bot]]

This PR is stale because it has been open 28 days with no activity. Remove stale label or comment or this will be closed in 14 days.

[jscarle]

I can't seem to remove the stale tag.

[jbogard]

The Contracts project can't be changed. Or at least, these changes aren't critical enough for me to update a package I've said will never be changed 🤣

[jscarle]

@jbogard Sorry about that, it was an oversight on my end. I've removed any changes to the Contracts project.

[github-actions[bot]]

This PR is stale because it has been open 28 days with no activity. Remove stale label or comment or this will be closed in 14 days.

[github-actions[bot]]

This PR was closed because it has been stalled for 14 days with no activity.