Improve migration guide

[mojito317]

Checklist

• [x] Tick to sign-off your agreement to the Developer Certificate of Origin (DCO) 1.1
• [ ] Added tests for code changes or test/build only changes
• [ ] Updated the change log file (CHANGES.md|CHANGELOG.md) or test/build only changes
• [x] Completed the PR template below:

Description

My goal was to improve the migration guide dispersing the fog around the support of the retry feature an error handling.

Approach

• applied code style on the links for new operations d18ea7181621ee302b6b6edce6752f8e4676dbbd
• fixed incorrect links (8c0294d1ff261987b63e7f288dbcd7b913f74a68):
  • postReplicate was excluded from new SDKs, so I pointed replication().trigger() to the putReplicationDocument operation
  • link for postChanges changed
  • the link for postPartitionFind has changed
• Added a warning about the error handling 0ac0f56d0dcb89ac1b8109cae913f7cf938cbde1
• Added a note about Replays interceptors replacement 0ac0f56d0dcb89ac1b8109cae913f7cf938cbde1

Schema & API Changes

• "No change"

Security and Privacy

• "No change"

Testing

• N/A build or packaging only changes

Monitoring and Logging

• "No change"