chore: add tcx info in BPF_PROG_TYPE_SCHED_CLS.md

[ianchen0119]

No description provided.

[ianchen0119]

This pull request includes an addition to the docs/linux/program-type/BPF_PROG_TYPE_SCHED_CLS.md file to document the new tcx BPF fast path with BPF link support introduced in kernel v6.6. The changes provide detailed information on the new features and relevant return codes.

Documentation updates:

• Added a section on tcx support, including a table of program types, attach types, ELF section names, and sleepable status.
• Included the definition of return codes for tcx programs with a code snippet.
• Provided a link to further details on tcx from the LSFMM+BPF Summit Recap and Video.

[ianchen0119]

@dylandreimerink

Could you please help to review this PR? Many Thanks!

[dylandreimerink]

Changes look good. I have fixed CI on master, could you rebase your changes to fix CI?

[ianchen0119]

@dylandreimerink done!

[dylandreimerink]

Thanks, sorry for the slow replies, holidays and all. Now that CI can actually run, the spellcheck isn't happy. I suggest adding tc, tcx and Netkit to the dictionary. LSFMM is not really a common word, so I suggest wrapping it in <nospell></nospell> to ignore it.

[ianchen0119]

Hi @dylandreimerink

I just updated the PR.
Would you please help to approve the CI workflow?

Thanks!