How can we return multiple tag variables with proper binding?
At first we thought we needed this every time:
```marko
<let/count=0 />
<let/message="hello" />
<return={
count,
countChange(newCount) {
count = newCount;
}
message,
messageChange(newMessage) {
message = newMessage;
}
} />
```
Attribute tags to the rescue!
```marko
<let/count=0 />
<let/message="hello" />
<return>
<@value count:=count message:=message />
</return>
```
This looks pretty good in concise mode
```marko
let/count = 0
let/message = "hello"
return
@value count:=count message:=message
```
And it extends to `const`, which can be used in interesting ways
```marko
let/count = 0
const/counter
@value count:=0 reset() { count = 0 }
button onClick:=counter
-- ${counter.count}
button onClick=counter.reset
-- Reset
```