docs(user-guide): update link to Helm hooks documentation

[tongpu]

Just a quick update to point the link for Helm hooks documentation to the Helm documentation page instead of an outdated branch in helm/helm.

Checklist:

• Either (a) I've created an enhancement proposal and discussed it with the community, (b) this is a bug fix, or (c) this does not need to be in the release notes.
• The title of the PR states what changed and the related issues number (used for the release note).
• I've included "Closes [ISSUE #]" or "Fixes [ISSUE #]" in the description to automatically close the associated issue.
• I've updated both the CLI and UI to expose my feature, or I plan to submit a second PR with them.
• Does this PR require documentation updates?
• I've updated documentation as required by this PR.
• Optional. My organization is added to USERS.md.
• I have signed off all my commits as required by DCO
• I have written unit and/or e2e tests for my change. PRs without these are unlikely to be merged.
• My build is green (troubleshooting builds).

[codecov]

Codecov Report

Base: 45.60% // Head: 45.60% // No change to project coverage 👍

Coverage data is based on head (0f5e7a6) compared to base (309654c).
Patch has no changes to coverable lines.

Additional details and impacted files

@@           Coverage Diff           @@
##           master   #11045   +/-   ##
=======================================
  Coverage   45.60%   45.60%           
=======================================
  Files         237      237           
  Lines       28914    28914           
=======================================
  Hits        13185    13185           
  Misses      13913    13913           
  Partials     1816     1816           

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[blakepettersson]

LGTM 👍