lighthouse mixed content documentation correction

[beagins]

Page Affected: https://developers.google.com/web/tools/lighthouse/audits/mixed-content

What needs to be done?

The example should be updated. The example as-is does not work and produces an error "Please provide a url".

lighthouse --mixed-content http://www.example.com

Rearranging the order of the parameters so that the url is the first param does cause the command to work as expected.

lighthouse http://www.example.com --mixed-content

After running this command, a HTML report is generated in the current working directory, as described.

[riginoommen]

What are these options full'|'mixed-content'|'perf in presets how it differs from lhci/cli presets