Improve manual installation instruction for windows

[corneliusweig]

Also

• remove trailing whitespace in docs
• add shebang in hack/release.sh
• ensure generated doc has no trailing whitespace

Fixes #1762

[codecov-io]

Codecov Report

Merging #1883 into master will not change coverage.
The diff coverage is 100%.

@@           Coverage Diff           @@
##           master    #1883   +/-   ##
=======================================
  Coverage   50.15%   50.15%           
=======================================
  Files         168      168           
  Lines        7363     7363           
=======================================
  Hits         3693     3693           
  Misses       3312     3312           
  Partials      358      358

Impacted Files	Coverage Δ
cmd/skaffold/app/cmd/build.go	68.18% <100%> (ø)	⬆️

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[container-tools-bot]

Error creating deployment, please see controller logs for details.

[container-tools-bot]

Please visit http://35.236.113.232:1313 to view changes to the docs.

[container-tools-bot]

Error creating deployment, please see controller logs for details.

[balopat]

Thank you!!