Fix missed rst->md numbered list syntax for m.room.server_acl

[anoadragon453]

There was some left-over RST syntax which was causing a numbered list to have broken formatting:

This PR applies the equivalent markdown syntax.

Preview: https://pr3681--matrix-org-previews.netlify.app

[uhoreg]

Looks like it does exactly what it says on the box.

[turt2live]

please can we use real numbers and not markdown trickery

[anoadragon453]

please can we use real numbers and not markdown trickery

Oh, why do you prefer real numbers? I find the advantage of this is that items can be added to the list without having to reflow the numbers.

[turt2live]

It's so that the raw markdown can theoretically be used as a reference without the HTML rendering, and to make review easier down the line when we say "Rule 4 is changed"

[anoadragon453]

Thank you, I hadn't considered those points. That sounds like reason enough to change it.

[turt2live]

thanks :)

This should also get a typos changelog (copy/paste from an existing one)

[turt2live]

oh, it has a changelog and I'm blind.