fix(plugins/plugin-kubectl): kubectl explain -h should render as usag…

[starpit]

…e in sidecar

Fixes #4211

Description of what you did:

My PR is a:

• 💥 Breaking change
• 🐛 Bug fix
• 💅 Enhancement
• 🚀 New feature

Please confirm that your PR fulfills these requirements

• Multiple commits are squashed into one commit.
• The commit message follows Conventional Commits, which allows us to autogenerate release notes; e.g. fix(plugins/plugin-k8s): fixed annoying bugs
• All npm dependencies are pinned.

[codecov]

Codecov Report

Merging #4222 into master will decrease coverage by 0.08%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #4222      +/-   ##
==========================================
- Coverage   59.35%   59.27%   -0.09%     
==========================================
  Files          74       74              
  Lines        2399     2399              
  Branches      582      582              
==========================================
- Hits         1424     1422       -2     
- Misses        748      750       +2     
  Partials      227      227              

Impacted Files	Coverage Δ
packages/core/src/util/i18n.ts	56.00% <0.00%> (-8.00%)	⬇️
packages/core/src/repl/tab-completion.ts	73.33% <0.00%> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update bfa96ed...4080f1e. Read the comment docs.