<macro> must have a name

[mlrawlings]

<macro> now expects its first attribute to be its name (regardless of whether it has arguments or not), if there are no attributes or the first attribute has a value (ex. test=123), then it throws an error.

✅ good:

<macro greeting>
    Hello!
</macro>

<macro greeting()>
    Hello!
</macro>

<macro greeting(name)>
    Hello ${name}!
</macro>

❌ bad:

<macro async=true>
    Uh-oh!
</macro>

<macro test=123 greeting(name)>
    Uh-oh ${name}!
</macro>

<macro>
    Uh-oh!
</macro>

[patrick-steele-idem]

Thanks! New version published with improvement and CHANGELOG.md updated.