Missing "=" for attribute generates confusing syntax error

In the HTML coding challenges users are often missing the "=" sign after an attribute like this:

``` html

```

The error message is: "_It looks like your opening tag doesn't end with a >._"
Which is a very confusing message, and causing users to make a lot of strange changes to their code, trying to get the syntax error to go away.

One option might be to change the message in this case, but I'm also thinking it's a better idea to do an instructional video on handling common errors and problems as suggested by @kevinbarabash in this issue: https://github.com/Khan/live-editor/issues/445

A video explaining how to interpret the messages - especially the confusing ones - given by Oh Noes guy, would help prevent a lot of issue reports that are syntax related.

@pamelafox any thoughts on this?

Reproduce the missing-equals example in the HTML coding challenges and review the related discussion in issue #445. Determine whether the work is a clearer syntax message, an instructional video, or both; completion should be verified by confirming the confusing error is addressed for this example.

Written by the indexing model from the issue text.