docs(vrl): decode_charset.cue, encode_charset.cue documentations

[powerumc]

Summary

The documentation for PR vectordotdev/vrl #1162 has been completed.

Change Type

• Bug fix
• New feature
• Non-functional (chore, refactoring, docs)
• Performance

Is this a breaking change?

• Yes
• No

How did you test this PR?

I ran the local web server(in the website directory, using make serve) and verified the documentation for the decode_charset and encode_charset functions.

• {BASE_URL}/docs/reference/vrl/functions/#encode_charset
• {BASE_URL}/docs/reference/vrl/functions/#encode_charset

Does this PR include user facing changes?

• Yes. Please add a changelog fragment based on our guidelines.
• No. A maintainer will apply the "no-changelog" label to this PR.

Checklist

• Please read our Vector contributor resources.
• If this PR introduces changes Vector dependencies (modifies Cargo.lock), please
  run dd-rust-license-tool write to regenerate the license inventory and commit the changes (if any). More details here.

References

• vectordotdev/vrl repo PR: feat(stdlib): add encode_charset, decode_charset functions vrl#1162

[bits-bot]

All committers have signed the CLA.