Flags defined in BaseAzureAction / BaseFunctionAppAction do not show up in --help

[ankitkumarr]

Flags such as --slot, --access-token etc that are defined for the parser in base classes do not show up in the --help output.

cc: @ahmedelnably

[MaybeSacred]

This is especially confusing for new users, as it's not clear from the help text how to deploy to different deployment slots using func azure functionapp publish. New users (like myself) won't have the context to know about these additional switches

[sebader]

Came to this issue because I tried to figure out whether slots are supported through the core tools. Guess this means they are... :)
So yes: Please update the --help (and the public docs)! Also things like --python (or other languages) are not mentioned anywhere.