chore: Remove docs/package-lock.json

[thernstig]

I learned that a workspace-aware project should only retain a package-lock.json file at the root of the repository, see comment at #1984 (comment)

The docs/ directory in this repository is a workspace:

cli/package.json

Lines 5 to 8 in f5a7360

	"workspaces": [
	"docs",
	"workspaces/*"
	],

Should https://github.com/npm/cli/blob/latest/docs/package-lock.json thus be removed?

[ruyadorno]

good catch! thanks @thernstig