Feature request: {#var: if-zero | if-one | if-two | if-three | else }

This is looking increasingly useful rn; essentially an inline switch statement. I suggest using the # modifier to denote it.

The worst thing about it is

```
{#bool: if-false | if-true }
{ bool: if-true | if-false }
```

and

```
{#knot: if-never-seen| if-seen-once | if-seen-twice }
{knot: if-seen | if-not-seen}

```

... but in both cases, the ambiguity isn't too bad, and the usefulness is (hopefully!) fairly apparent!

jon