[css-gaps-1] Use commas instead of slashes for *-rule shorthands. #11496

[kbabbitt]

No description provided.

[kbabbitt]

@tabatkins I think you mentioned during the discussion that you had a grammar nit to raise?

[tabatkins]

GitHub UI is busted for multi-line suggestions (constantly complains that I'm "adding suggestions to deleted lines"), but here you go:

		<dfn>&lt;gap-rule-list&gt;</dfn>        = <<gap-rule-or-repeat>>#
		<dfn>&lt;gap-auto-rule-list&gt;</dfn>   = <<gap-rule-or-repeat>>#? , 
								             <<gap-auto-repeat-rule>> , 
								             <<gap-rule-or-repeat>>#?
		<dfn>&lt;gap-rule-or-repeat&gt;</dfn>   = <<gap-rule>> | <<gap-repeat-rule>>
		<dfn>&lt;gap-repeat-rule&gt;</dfn>      = repeat( <<integer [1,∞]>> , <<gap-rule>># )
		<dfn>&lt;gap-auto-repeat-rule&gt;</dfn> = repeat( auto , <<gap-rule>># )
		<dfn>&lt;gap-rule&gt;</dfn>             = <<line-width>> || <<line-style>> || <<color>>

• <gap-auto-rule-list> needed commas between the terms. (They're implicitly omitted if the <gap-rule-or-repeat> is omitted.)
• Removed all the unnecessary brackets. (This was just a nit, but having brackets does suggest you need brackets, and it's a little confusing when that's not true.)

[kbabbitt]

Thanks @tabatkins, I incorporated your suggestions and merged.