feat(max-attributes-per-line): singleline.allowFirstLine option

[privatenumber]

What rule do you want to change?
max-attributes-per-line

Does this change cause the rule to produce more or fewer warnings?
More

How will the change be implemented? (New option, new default behavior, etc.)?
Lower the minimum value on singleline/singleline.max to 0 on the schema.

Update:
Add a singleline.allowFirstLine option that defaults to true, but prevents single attributes from being on the same line if set to false.

Please provide some example code that this change will affect:
When setting singleline.max = 0, the following should be marked incorrect:

Update:
When setting singleline.allowFirstLine = false, the following should be marked incorrect:

<template>
	<component name="John Doe" />
</template>

What does the rule currently do for this code?
Currently, can't set singleline to 0 because of the schema validation.

What will the rule do after it's changed?
Correct it to:

<template>
	<component
		name="John Doe"
	/>
</template>

Additional context

• This was working in prior versions of ESLint that did not enforce the JSON schema on options. But since upgrading ESLint, this appeared to be a regression. Since it's not a regression in this plugin, I labeled this as a feature request.

• This is style used by a large codebase I'm contributing to.

[ota-meshi]

Thank you for this PR!
I think it easier for users to add a singleline.allowFirstLine option similar to multiline.allowFirstLine option.
What do you think?

[privatenumber]

Yeah that definitely makes more sense when trying to grasp the options.

Will update to allowFirstLine. Thanks!

[privatenumber]

Now that I'm working on updating the docs, I'm second-guessing whether it makes sense.

It's a little strange that a "singleline" rule enforces the multiline behavior:

['error', {singleline: { allowFirstLine: false }}]

<template>
	<component
		name="John Doe"
	/>
</template>

I still think it's an improvement over max: 0 though.

[ota-meshi]

Thank you for changing this PR! LGTM