Add box-tree-api

[browser-specs-bot]

URL

https://drafts.css-houdini.org/box-tree-api/

Rationale

• See repository: w3c/css-houdini-drafts
• Would-be shortname: box-tree-api

Additional properties

{}

[browser-specs-bot]

The update could not be built:
Error: Fetching https://drafts.css-houdini.org/box-tree-api/ failed with HTTP code 504
at default (file:///home/runner/work/browser-specs/browser-specs/src/load-spec.js:51:13)
at async fetchInfoFromSpec (file:///home/runner/work/browser-specs/browser-specs/src/fetch-info.js:342:7)
at async ThrottledQueue.runThrottled (file:///home/runner/work/browser-specs/browser-specs/src/throttled-queue.js:78:22)
at async Promise.all (index 0)
at async Object.fetchInfoFromSpecs [as fn] (file:///home/runner/work/browser-specs/browser-specs/src/fetch-info.js:477:18)
at async fetchInfo (file:///home/runner/work/browser-specs/browser-specs/src/fetch-info.js:515:7)
at async Object.runInfo [as run] (file:///home/runner/work/browser-specs/browser-specs/src/build-index.js:218:20)
at async generateIndex (file:///home/runner/work/browser-specs/browser-specs/src/build-index.js:386:13)
at async buildDiff (file:///home/runner/work/browser-specs/browser-specs/src/build-diff.js:267:5)
at async build (file:///home/runner/work/browser-specs/browser-specs/src/build-diff.js:153:7)