Update remaining docs site locations to call out .net 8 support

[nrcventura]

Describe the story, please be clear on scope of the story.

When we initially updated the doc site to call out our .net 8 support, we missed a few locations in https://docs.newrelic.com/docs/apm/agents/net-agent/getting-started/net-agent-compatibility-requirements-net-core/

We need to update those remaining locations. Some of the locations include the section where we specifically call out .net targets, and aspnetcore support.

Acceptance Criteria

Every place where we call out our .net 6 support should also call out our .net 8 support.
Every place where we call out our aspnetcore 6 support should also call out our aspnetcore 8 support.

Dependencies

N/A

Describe Design Consideration/Limitations

N/A

Additional context

N/A

Estimates

Please provide initial t-shirt size: Small

[workato-integration]

https://new-relic.atlassian.net/browse/NR-190877

[workato-integration]

Work has been completed on this issue.