Improve sample curl commands with Maven artifacts fetching

What does this MR do and why?

Missing artifactId and version in the path section was confusing for people trying to use it (even though, it is properly described in a table above The Maven package path, in the format <groupId>/<artifactId>/<version>.).

Additional information

There might be still a problem with the JAR versioning scheme for SNAPSHOTs in Maven (with timestamp), but it is a separate issue and I didn't want to mix it in one MR.

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This is just a minor improvement in the existing documentation.

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