chore(docs): update unpublish docs with both commands, removing policy info from cli docs, and added reference to unpublish policy docs

[nomadtechie]

• Updating docs unpublish docs to with examples of both unpublish commands
• Removing policy info from cli docs to centralize policy in policy docs
• Added reference to unpublish policy docs

[mikemimik]

The small inclusion of the man pages notation.

As well as the update to the command usage (lib/unpublish.js):

- unpublish.usage = usage('npm unpublish [<@scope>/]<pkg>[@<version>]')
+ unpublish.usage = usage(
+   'unpublish',
+   '\nnpm unpublish [<@scope>/]<pkg>[@<version>]' +
+   '\nnpm unpublish [<@scope>/]<pkg> --force'
+ )

[npm-deploy-user]

	angular-quickstart			app-large			app-medium			ember-quickstart			react-app
	prev	current	status	prev	current	status	prev	current	status	prev	current	status	prev	current	status
initial install	41s	37.5s	✅	39.5s	36.9s	✅	34.5s	31.6s	✅	28.1s	25.6s	✅	33.5s	30.2s	✅
repeat install	9.6s	8.4s	✅	8.6s	7.6s	✅	8.3s	8.2s	✅	7.7s	7.1s	✅	9.1s	8s	✅
with warm cache	32.3s	27.5s	✅	33.8s	31.5s	✅	31.3s	27.9s	✅	23.4s	22.4s	✅	29.1s	27.7s	✅
with node_modules	9.2s	9.8s	✅🐌	8.6s	7.3s	✅	9s	7.2s	✅	7.8s	6.4s	✅	9.4s	8.7s	✅
with lockfile	32.6s	28.3s	✅	31s	29.2s	✅	29s	26.7s	✅	21.7s	20.1s	✅	27.4s	24.6s	✅
with warm cache and node_modules	9.3s	7.7s	✅	7.9s	7.3s	✅	8.4s	6.9s	✅	7.6s	6.5s	✅	9.2s	7.6s	✅
with warm cache and lockfile	24.7s	21.6s	✅	26.3s	25.1s	✅	24.3s	22.6s	✅	17.8s	14.9s	✅	21.3s	19.5s	✅
with node_modules and lockfile	10.1s	8.8s	✅	9.8s	8s	✅	8.6s	7.9s	✅	7.8s	7s	✅	9.7s	8.3s	✅

[mikemimik]

Note: will be moving this from Sprint 2 -> Sprint 3 and rolled into the next release.

[darcyclarke]

@nomadtechie noticed this got missed from our latest release & we figured out why; This PR has failing tests so it was skipped in the triage last week. Apologies for that. If we can fix whatever the issues are w/ linting/test coverage we'll pull this in next.

[nomadtechie]

@nomadtechie noticed this got missed from our latest release & we figured out why; This PR has failing tests so it was skipped in the triage last week. Apologies for that. If we can fix whatever the issues are w/ linting/test coverage we'll pull this in next.

lint error is resolved now - thanks again @darcyclarke !