ISSUE-8688: [Doc]Contradictory documentation of websocket features

[sijie]

Original Issue: apache#8688

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Describe the bug
at https://pulsar.apache.org/docs/en/client-libraries-websocket/ is written:

Through WebSockets you can publish and consume messages and use all the features available in the Java, Go, Python and C++ client libraries.

When looking at the Pulsar client feature matrix
at https://github.com/apache/pulsar/wiki/Client-Features-Matrix

the picture looks different: Websocket seems to offer by far the least number of features.

Expected behavior
Same statements of the documentation at both places.

Screenshots

Additional context
of course Feature Matrix is for 2.5.0, but latest version of pulsar would not have "solved" all red crosses in Matrix :-)

but for at least one red cross there is an open issue which contains a pull request: apache#8247
an other issue asks for feature parity apache#2678
which would of course makes this issue obsolete...