[html] HTML breadcrumbs don't work right when optional end tags omitted

• VSCode Version: 1.42.0-insider
• OS Version: Linux Mint 19.3

Steps to Reproduce:

1. Create an HTML document. Sprinkle liberally with <p>, <li> (inside of <ul> or <ol>, obviously), <tr> or <td> inside of <table>, and any other elements noted in the HTML5 spec as having optional end tags (see https://html.spec.whatwg.org/#syntax-tag-omission).
2. If you closed the various tags above with their end tags (e.g., </p>), then run the page through something like HTML Tidy (I am using v5.7.28), passing in the --omit-optional-tags yes argument.
3. Open the reformatted file in VSCode and navigate somewhere where there are multiple <p> or <li> or similar in a row. Note that there will be a breadcrumb for each open tag, because VSCode is apparently looking for end tags to close off the element, even though it is not required.

In a complex document, this make VSCode breadcrumbs pretty worthless. Here is an example, before a Tidy reformat, with focus on the third list item element in the fourth paragraph (note breadcrumbs working as expected):

And here are the breadcrumbs after the Tidy reformat, with focus on the same list item element:

Does this issue occur when all extensions are disabled?: Yes

[bitwiseman]

v1.11.0 of js-beautify fixes the formatting issue that @nikeee commented on. This doesn’t fix the breadcrumb issue.

[aeschli]

Related issue in https://github.com/microsoft/vscode-html-languageservice/issues/63

@bitwiseman Sorry for only see your question now. Yes, that needs to go into the HTML parser. If you want to give it a try, that would be fantastic.