Empty anchor (<a id="foo></a>) tag creates superfluous reference entry

[ralfhandl]

Description of problem

URL to affected spec or repo:

Source showing the problem:

https://github.com/ralfhandl/respec-experiments/blob/c94de45be239521a56f3c35f438c6d9d1689aab7/src/example.html#L94

Adding a space between the opening and closing tag worked in older respec versions and doesn't work now.

Current workaround: <a id="foo" class="logo"></a> which doesn't seem to have negative side-effects.

What happened (e.g., it crashed)?:

Superfluous/wrong reference entry "css" is created:

Expected behavior (e.g., it shouldn't crash):

Just create the anchor, don't create a buggy reference entry.

Optional, steps to reproduce:

1. clone https://github.com/ralfhandl/respec-experiments
2. git checkout bug/empty-anchor
3. view file src/example.html in browser

[ralfhandl]

Alternative workaround: use <span id="foo"></span> which also doesn't seem to have negative side-effects.