Need better docs on how to do declarative validation

[ebidel]

Took me a while to piece it together. The gist is:

<template is="auto-binding">
  <paper-input-decorator label="Number" floatingLabel
                         error="is not a number" 
                         isInvalid="{{!$.input.validity.valid}}">
  <input id="input" is="core-input" pattern="\d*">
</paper-input-decorator>
</template>

<script>
  CoreStyle.g.paperInput.invalidColor = 'red';
</script>

[wildfiremedia]

Is there any docs on pattern usages?

[morethanreal]

How does 893d76d look?

I also realized that I forgot to add paper-input-decorator docs to index.html :(

[morethanreal]

I added autoValidate in 255980d which should make this a lot more straightforward.