Allow empty string text nodes

Currently, if you try to render a node like this: ```js text('') ``` It will go through this part of the code to get HTML escaped, however, because the `||` operator considers `''` a falsy value, it goes for `node.name` instead, which does not exist on a VDOM node. The first line in this `escapeHtml` function converts this `undefined` value to string, which ends up being the string `'undefined'`. I think this is a bug? Hope this helps!

Author: loteoo

src/index.js

@@ -251,7 +251,7 @@ export function renderer(view, state, actions) {
  footer: '',
  })
  } else if (node.type === 3) {
- out += escapeHtml(node.tag || node.name)
+ out += escapeHtml(node.tag != null ? node.tag : node.name)
  } else if (typeof node === 'object') {
  out += renderFragment(
  node.tag || node.nodeName,