fix(vdom): properly warn for step attr on input

[rwaskiewicz]

Pull request checklist

Please check if your PR fulfills the following requirements:

• Tests for the changes have been added (for bug fixes / features)
• Docs have been reviewed and added / updated if needed (for bug fixes / features)
• Build (npm run build) was run locally and any changes were pushed
• Unit tests (npm test) were run locally and passed
• E2E Tests (npm run test.karma.prod) were run locally and passed
• Prettier (npm run prettier) was run locally and passed

Pull request type

Please check the type of change your PR introduces:

• Bugfix
• Feature
• Refactoring (no functional changes, no api changes)
• Build related changes
• Documentation content changes
• Other (please describe):

What is the current behavior?

Stencil performs dev-time checking of the order of input element attributes. The check for the step attribute is incorrect, as it points to min

GitHub Issue Number: #2406

What is the new behavior?

fix indexOf call for the step attribute to look for the correct
attribute name.

hoist the check for value attribute to exit early if the attribute
does not exist, avoiding unneeded lookups of other attributes

Does this introduce a breaking change?

• Yes
• No

Testing

First, I built this branch, npm ci && npm run clean && npm run build && npm pack.

I spun up a new Stencil component library (npm init stencil -> component), ran npm i for the component, then installed the tarball generated from the previous call to npm pack

Replace the render fn in src/my-component.tsx:

  render() {
    // note 'step' is after 'value'
    return <input value={"Hello"} step={1}></input>;
  }

Run npm start in a terminal window whose cwd is the root of the Stencil component library that was spun up. Open dev tools in your browser of choice to see the err msg.

Similarly, removing 'step'/reordering the attributes removes the error message:

  render() {
    // note 'value' is after 'step'
    return <input step={1} value={"Hello"}></input>;
  }