pulumi-config: add page

[Denis-Kuso]

• The page(s) are in the correct platform directories: common, linux, osx, windows, sunos, android, etc.
• The page(s) have at most 8 examples.
• The page description(s) have links to documentation or a homepage.
• The page(s) follow the content guidelines.
• The page(s) follow the style guide.
• The PR title conforms to the recommended templates.
• Version of the command being documented (if known):

[CLAassistant]

All committers have signed the CLA.

[sebastiaanspeck]

Suggested change

	`pulumi config --config-file {{path/to/file}} rm-all {{key1}} {{key2}} {{key3}} ... {{[flags]}}`
	`pulumi config --config-file {{path/to/file}} rm-all {{key1 key2 ...}} {{[
	flags}}`

[Denis-Kuso]

This one seems to be missing a closing square bracket at the end of flags variable right?