Fix code in enable-dynamic-configuration-dotnet-core-push-refresh.md

[artemious7]

• await serviceBusProcessor.StartProcessingAsync(); was missing, so the example didn't work
• fix grammar, improve formatting

[prmerger-automator[bot]]

@artemious7 : Thanks for your contribution! The author(s) have been notified to review your proposed change. @MBSolomon

[learn-build-service-prod[bot]]

Learn Build status updates of commit 6809e05:

:white_check_mark: Validation status: passed

File	Status	Preview URL	Details
articles/azure-app-configuration/enable-dynamic-configuration-dotnet-core-push-refresh.md	:white_check_mark:Succeeded

For more details, please refer to the build report.

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[learn-build-service-prod[bot]]

Learn Build status updates of commit 0364a6a:

:white_check_mark: Validation status: passed

File	Status	Preview URL	Details
articles/azure-app-configuration/enable-dynamic-configuration-dotnet-core-push-refresh.md	:white_check_mark:Succeeded

For more details, please refer to the build report.

For any questions, please:

• Try searching the learn.microsoft.com contributor guides
• Post your question in the Learn support channel

[Court72]

@zhenlan

Can you review the proposed changes?

When the changes are ready for publication, add a #sign-off comment to signal that the PR is ready for the review team to merge.

label:"aq-pr-triaged"

@MicrosoftDocs/public-repo-pr-review-team

[zhenlan]

The change looks reasonable to me.

@amerjusupovic can you please help validate the code works as expected?

[amerjusupovic]

@zhenlan confirmed the example doesn't work currently, and with the changes it now works as expected where key-value updates are logged to the console.

[zhenlan]

Thank you for the verification, @amerjusupovic.

sign-off

[prmerger-automator[bot]]

Invalid command: '#sign-off'. Only the assigned author of one or more file in this PR can sign off. @MBSolomon