MINOR: [Release][Docs] Add clarification on some post release steps documentation

[raulcd]

Rationale for this change

Some outdated or missing clarifications when running the release.

What changes are included in this PR?

Minor documentation clarifications on publishing JS and updating docs.

[assignUser]

Thanks!

[ursabot]

Benchmark runs are scheduled for baseline = 7a3c66a and contender = 9be961a. 9be961a is a master commit associated with this PR. Results will be available as each benchmark for each run completes.
Conbench compare runs links:
[Finished ⬇️0.0% ⬆️0.0%] ec2-t3-xlarge-us-east-2
[Failed ⬇️1.52% ⬆️0.58%] test-mac-arm
[Failed ⬇️0.46% ⬆️0.0%] ursa-i9-9960x
[Finished ⬇️0.51% ⬆️0.48%] ursa-thinkcentre-m75q
Buildkite builds:
[Finished] 9be961a2 ec2-t3-xlarge-us-east-2
[Failed] 9be961a2 test-mac-arm
[Failed] 9be961a2 ursa-i9-9960x
[Finished] 9be961a2 ursa-thinkcentre-m75q
[Finished] 7a3c66ac ec2-t3-xlarge-us-east-2
[Failed] 7a3c66ac test-mac-arm
[Failed] 7a3c66ac ursa-i9-9960x
[Finished] 7a3c66ac ursa-thinkcentre-m75q
Supported benchmarks:
ec2-t3-xlarge-us-east-2: Supported benchmark langs: Python, R. Runs only benchmarks with cloud = True
test-mac-arm: Supported benchmark langs: C++, Python, R
ursa-i9-9960x: Supported benchmark langs: Python, R, JavaScript
ursa-thinkcentre-m75q: Supported benchmark langs: C++, Java

[kou]

We may be able to use ${github_url}/pull/new/asf-site...${branch_name} for this.